Been an avid user of both Pickem and Survivor for a long time - I'd previously run a predictions league on my site from before I switched to Xenforo and I couldn't do without.
If you are looking to add interest to your sports related site, or even a site dedicated to another genre that would benefit a Fantasy Sports distraction... this is for you.
Very stable and trustworthy in terms of quality, it's install and forget in the way of tweaking and maintenance, you'll be able to set it up and enjoy using, rather than spending hours fixing or shoehorning the addon to suit.
You'll not need support, but if you do, I know from experience that the author is attentive and passionate about his work.
I'm not someone who gives 5/5 for the sake of it, but happy to in this instance.