I'll preface this by saying that Susan and I have been actively evaluating new platforms for about a year. We've been developing/extending our community solution (currently vB 3.8 + WP/Joomla! and PHPMyDirectory) for about 5-6 years. Our community is how we make a living. It pays our mortgage and all our bills, so it's both a business AND a labor of love. I've tried very hard to give an honest comparison of the two systems based on our experience. Susan and I would very much appreciate hearing what others think from *their* experience and perspective. Obviously vB 4 is not even vaguely in the running. This isn't an emotional decision it's based on hard cold facts about the platform, it's resource consumption, it's likely future, and how freaking impossible it is to work with if you want to modify/extend it. Our take, based on working with both systems for about a month, popping for a "Hosted Community" with the full IPS Suite loaded on it (if you get the "Plus 40" for $29.99/month and pay $5/month more you can get the entire package including IP.Content and IP.Nexus) is: IPS: Benefits of IPS: IPS is a very mature system with a LOT of capability. The development pace is rapid, and they have come a long way from a year or two ago. The have importers, and seem to provide excellent service on tickets, the forum based help is spotty, but as long as tickets work that's fine with me. IP.Nexus is a real gem, seriously impressive what you can do with an integrated ecommerce solution, next version has ala cart ad sales, even the ability to use as the front end for hosting reselling. Awesome stuff. The mobile skin and built in iphone app are definite benefits. The IP.Content article system being able to promote from forum topic to an article and fully integrate the comments and topic replies is a major plus. They have a great search system that is fully integrated across the whole system (except for only searching a single IP.Content database at a time) as well as excellent support for Sphinx. Their gallery is getting a major upgrade, though it lacks meaningful integration with the rest of the system. It's very nice, and works well with the mobile skin/app. Downsides to IPS: The 3rd part dev community is very VERY thin. The core products change so frequently, and break skins/mods with incredible rapidity. The end of last year IPS was releasing a major upgrade to one of their apps EVERY WEEK! That has driven a tremendous # of the Mod and skin developers away from the IPS platform simply because they can't afford to be updating everything they do so often. There are currently a LOT more mods for XF already built, than there are 3rd party mods that work with the current version of IPS. The IPS platform (while it makes vB 4 look like stone tablets and chisels) is somewhat dated, and despite all it's technical capability, feels clunky to me personally. There are a lot of inconsistencies between apps, and the CSS is really hard to work with. The promise of IP.Content is largely unfulfilled as it's very awkward to deal with. The documentation is quite lacking, and it's flat out hard to work with. In short: If you like the stock IPS system out of the box you will probably love IPS and it's what you should go with, it's a great product. But if you want to extend it in any significant ways to meet your communities specific needs, you are likely to be fighting an uphill battle and a rough time finding someone to help you with the development, and a rougher time maintaining your customizations. Same for styling, if you don't like the stock skin or a fairly simple variation based on the stock skin, you CAN find some custom skin devs, but they are expensive and maintenance will be a major problem with every app release requiring significant work to maintain the skin multiple times a year. IPS has some very technically capable solutions. IMO They need a better UI designer (little inconsistencies like things not being exactly aligned and the CSS being hard to work with). XF: Benefits of XF: XF is FUN. Seems shallow, but using XenForo is a very engaging experience. The #1 goal for a forum (IMO) is to reward people for their efforts. They need to feel appreciated by their peers, they need a sense of affirmation. XF does that better than any system out there, hands down. In my opinion, this is a crucial thing, hard to achieve and absolutely priceless for a community builder. The community. The XF 3rd party dev community is bursting with energy and people getting mods built. XF is built from the ground up to be modification and styling friendly, that that's a benefit that will draw the modification community in droves.. As XF has been built from the ground up with a fully modern design with a single, well architected CSS styling plan in place, it's very easy to customize the look/feel of the forum. The ability to put virtually ALL your styling changes in a single extra.css file means that XF upgrades have very VERY little impact on custom styles. Once you get below the surface of the ACP and look at the templating system, you quickly find just HOW powerful the system is. It's designed so that you can take any part of the system and extend it (both templates AND code) without modifying (hacking) the original. Again, that will make it a lot easier for mod developers to maintain their mods ad XF upgrades. XF is built as a platform like IPS. Kier and Mike have said from the beginning that they will will building a CMS, Gallery etc. Based on the best of breed nature of the Forum component, I have a high confidence level that those components will also be innovative and best of class. Looking at how fast their development cycle is, and how fast they built the whole platform AND the Forum component on top of that platform, I'm willing to bet that other parts of the platform will be available much faster than many people think. The SEO is superb out of the box, the fully semantic markup is the best we've seen. Downsides to XF: It's new. As it's not *quite* gold release (though I feel sure that it will be very shortly), a lot of Devs are waiting until they have final code in their hands before putting out their mods. There is a degree on uncertainty regarding the future of XF based on the legal disputes with IB. Personally, after reading the pertinent documents, I think IB is clearly gaming the legal system in an attempt to bleed XF dry before they really get rolling. I think they will fail, but it's a legitimate concern that must be considered as a person who has a BUSINESS building and running a community (as you and Susan and myself do). XF as a platform is nowhere *near* as comprehensive in functionality as IPS, nor do they have the corporate resources that Invision Power Systems has. Migrating a complex community to XF is currently going to be a somewhat complex, phased process. To start the process requires a level of faith in the platform and it's future development that many will be uncomfortable with. Conclusion: After working with our IPS installation for a couple weeks, getting a feel for what's involved in making it what we want for our community, we came back to take another good hard look at XF. Honestly, I wish it was an easier decision, IPS is a GOOD system, with a ton of capability (esp IP.Nexus if you are selling ads and or any memberships or tangible/digital goods). In two days we made more progress in XF than we had in 1-2 weeks in IPS. If *we* can do things that much faster, a real developer will be able to give us *far* more bang for our buck, IMO. At the end of the evaluation we asked ourselves 2 questions: Would you regret going with the other platform later? If we went with IPS: Yes. We'd always wonder how much better the community would have grown on XF. If we went with XF: We'd miss the capability of IP.Nexus most. But we built more with XF pages in 1 day than we did with IP.Content in a week. Which do you think will encourage community participation more? XF. Hands down. IPS relies too much on blocks to "integrate" things. Likes/Alerts system >> Rep. As a final reality check we chatted with a developer that's a good friend of ours that both runs his own vB forum and is looking to move. He said that he's looking at XF, and is very excited by the platform. He's never looked at IPS though so that's not a comparison, just an opinion on the XF side. What it comes down to is both are good systems. VERY good systems. Both make vB 4 look like stone tablets and chisels. But we've been doing this for 5-6 years now, and we've learned that a modern system, built right from the start is a better fit for us. We never... NEVER seem to be able to use an out of the box system, we always push the envelope. For us, that makes IPS less of a good fit than XF. What about others looking at the same choice? What have you found?