It's all personal opinion, naturally, but I've seen three or four people (including my girlfriend!) drop recently citing an inability to keep up. They're people I share games with, so I have a good impression of what their opinions on speed are. After all, one person's 'medium' is another's 'fast' and another's 'slow'.

It does sound like a great game, but especially if the events are where it speeds up, I couldn't last -- my home game is the same way, and I'd have to give my priority there.