It's a very nice hardware for its money. I think it's superior to Oneplus One when it first came out. Screen is nicer, build feels sturdier, and getting really regular updates so far. If you want to keep it less than $400 - this is a good phone that gets FHD 5.5". 1.8Ghz with 2GB has been a nice model to play with.
I read some early reports these phones had very weak wifi, with many users suffering constant drop outs, after experiencing this frustrating issue on an HTC One X several years ago I stopped looking at the zenfone2. Anyone experiencing this or know if its been resolved?