I initially felt corralled into installing it but now I use it quite frequently to participate in small group discussions with my friends. Actually, I should clarify: it's almost exclusively one group discussion that we use to organise our social lives (last-minute day trips at the weekends, beers after work, that sort of thing). Email has become fragmented (not universal; everyone has a number of accounts), there is no group option on SMS, and Twitter is too public. There isn't a comparable communication medium in use within my social circle.
I find the app experience pretty reliable and straight-forward. I especially like the option to 'snooze' chats for an hour or two (I'm trying to get some work done and my friends are all telling jokes) or until the next morning (I'm engaged this evening and don't want my phone pinging all the time).
(As it appear to be relevant and give context to this discussion, I'm a late-20s English male.)
I mean, that's nice and all, but like most things which have a utility tied to their network size, the quality of the app is largely irrelevant. If someone sends me an fb message to update me on where we're meeting, I want to see that right away regardless of my dislike of the UI.
