I've just checked my Appsumo account and see that the startup plan has been downgraded to basic. Will customers after the 1000 mark get anything or are you guys planning to refund?

(I think also think it is wrong of you guys to modify invoices which is supposed to be a record and agreement of a transaction.)

For other people on the fence, I'd suggest getting this now while you still can! I loved using Mixpanel in the past (although, I did think it was a bit pricey ;-)). The fact that I could send in events from my server made it far superior to GA. It meant that I could, for example, build funnels for emails I was sending out (send -> open -> click -> completion). Their HTTP API was easy enough to use that I wrote my own lisp (drakma-based) library to interact with it in under a few hours.

They used to have some scaling pains (multiple days delay on getting data processed), but that was all fixed towards the end. The support is great too - I got Suhail on the phone instantly when I was having trouble with something.