This is a really hard choice because both have their strengths and weaknesses. I tried Nobita for a long time. It has many more features including essential features for content discovery which Snog does not have. Nobita probably has 10 times as many features. Nobita functional design is much better than snog. But coding quality of Snog is much cleaner. Nobita does not always accept a bug report and sometimes you need to try really hard to get your bug accepted. With Nobita it is needed to always test a new release on your development site, because new releases always contain many bugs. The same can be said for any addon, but its more true for Nobita.
After I gave up on Nobita due to aforementioned reasons I tried Snog and even invested in an importer, but then found out there were significant issues with it as well. One issue was the choice to use user permissions per node for each group member, which in my case means thousands of user permissions per node. After having the code of both evaluated by a senior developer I concluded that a move from Nobita to Snog was not a good idea. I would have 10 times less features, my group activity would be as hidden like in vbulletin and still encounter issues. I originally planned to have addons to snog groups created to make up for the features that I need, but I got the strong impression that snog did not welcome the idea. (which is 100% his right as its his addon)
Now I have returned back to nobita. I intent to bring it live in the very near future after all issues are fixed. There are a number of webmasters actively testing out the software and reporting bugs to Nobita. Any issue that nobita does not solve will be solved by the senior developer I have an agreement with. So I do think that there will soon be a version of Nobita groups that I can run on my big board.
IMHO what Nobita needs is a feature lock and a number of maintenance releases only.
I've not tried Snog's solutions, but I agree with Alfa's assesment of Nobita's add on.
The solution is there needs to be a rock solid feature rich an extensible groups/clubs feature in XF core.
Users want it, admins want it and it drives activity. Let site admins get those page impressions and offload some of the forum moderation work to group admins before Facebook starts letting group admins monetise. They let news publishers monetise in the past, then ditched them when that didn't work. However groups are thriving, big time. It takes work to administer a group though, they've been slowing adding more features to groups and I predict it's only a matter of time before Facebook starts revenue sharing with facebook group admins in order to keep them alive, thriving, and on the platform.
Those same people are potential forum admins, getting swept up and tied to the facebook ecosystem. They'll grow their groups faster than many forums due to the one click join functionality of a billion user ecosystem, then once they reach a certain threshold it'll only take a click of a button before facebook starts putting money in their pocket. No messing around with adsense or figuring out the best place to put banner ads. Facebook will take care of all of that, the admin just needs to focus on the users and the content, ensuring continued activity.