I was at Twiistup and here is my review (as someone who has thrown well over 100 large events with over 20,000 attendees in total probably).

1. Good: It was in a large and interesting space: an airplane hanger.

2. Bad: There was no food--like none.

3. OK: The crowd was between ok and good. It wasn't a super VIP crowd, but it also wasn't people walking in off the street or all lawyers, recruiters and headhunters (although there were plenty of those!).

4. Bad: The sound system was bad and they had an MC running around trying to interview folks. That never works. Never try to speak over the crowd if you have an open bar, no seats and a bad audio system in a room with 50 foot ceilings.

5. OK: The booths were filled with companies that have been around for a while, so it didn't have the "new" feel. So, there was little to do in the space but drink and network.

6. Good: Cigars outside was a nice touch... folks seemed to like that

Overall I think the crowd had an OK to good time. The lack of food is just killer as that becomes the entire focus of the event and conversations ("is there food here?" as asked to me 20 times).

I don't think you can compare since they are two totally different events. One raises money for charity, the other raises awareness of new technology. The only thing in common are the attendees are hyper obsessed with Twitter.

This is kind of like asking, which is better Mahalo Answers or iTunes?

I'm going to vote Twestival because it was for charity.