Build 494 is working on my Mini almost perfectly. The only serious issue is the missing suspend function - I hope it'll be implented again in the near future.
As a Paperwhite user I'm a
CoolReader fan and I was sceptical about Koreader, but I'm really impressed now. Koreader makes the difference, using it the Kobo Mini has turned into a useful daily e-reader from the cute toy it was before.