I don't mind the price so much and they're not a bad doughnut (prefer the caramel ones from Bird's though) but what I really don't get is that there's always, always a huge queue to buy them.
That and the 30 minutes browsing time on a Sunday.
My mate rang Oceana to arrange entry, so it's probably best to do that with your chosen venue - you'll know in advance whether you can get in or not and no need to try and split up or whatever.
I think it depends, I was once turned away from a Wetherspoons because they were only letting in women and couples... Generally pubs are OK, but bars can be an issue.
Oceana cater for stag dos but I'm not sure if I'd class it as good...