Unity is fine. Its still missing a couple of tools that would be helpful to artists. But there are 3rd party plugins while we wait.
I'd say the tools are about as easy to work with as UDK or Cryengine. And graphically its fine, Not as good as cryengine, probably as good as UDK, And its about a billion times better looking than the antique gamebryo engine they used for New Vegas. That game doesn't even seem to have any sort of shadowing/lightmaps.
Dont worry, If this game sucks its not going to be because they used a popular well respected engine.