Rails Admin vs. ActiveAdmin [closed]
I vote for rails_admin. I like its looks and the fact that out of the box all the models are available for administration. The history feature is quite useful too.
Any project with Yehuda Katz as a mentor should be a safe bet.
I personally think the two could be merged, and have just raised the issue on both projects:
I think it would be great to take the best parts from both, and collaborate on the missing pieces.
I think it's really a matter of personal preference. More people are using rails_admin[*], but I prefer active_admin.
The reasons I chose ActiveAdmin were predominantly that it was developed with assumptions that I would make myself: using gems like devise and inherited_resources, and using a nice form builder (formtastic, though I would have chosen simple_form).
I actually prefer that not all models are exposed to the admin by default, though rails_admin supports that with 'config.included_models'.
[*] Watches/forks on https://github.com/gregbell/active_admin vs https://github.com/sferik/rails_admin - though the gap is closing.