I've considered installing MoinMoin for a small team at the office, so I'm glad you brought up the issue of its shortcomings. (If anyone objects to discussing MoinMoin here, please let me know; we might continue this discussion in private then.)
We use it at work. The ACL stuff is OKish, though I haven't kicked it really hard or tried to break it.
"OKish" sounds not very convinced; is it too complicated maybe? Or is it good at what it does, extreme security concerns aside?
Moin is way underfeatured compared to Mediawiki, though
In what way? It's missing MW-like templates (e.g. no parameters), that I know about - what else is there?
CamelCase fundamentally sucks
I'm not a fan of CamelCase either. But I think it can be avoided by simply using what in MoinMoin is called ["free links"] - and then either ignoring or !ManuallyEscaping the rare accidental CamelCase occurence. Also, CamelCase can be disabled altogether by replacing the default parser with a modified one (not sure whether there's any catch in that though): http://moinmoin.wikiwikiweb.de/ParserMarket/NoCamelCase
-- F.