If you are not sure if you should install it for the time being, you shouldn't. The os still has bugs and it may not be the best for daily use.
That being said, I have it on my 920 (my main phone) and I like it. There are bugs and the stability is less than 8.1 in general. If you are too excited about it and don't mind the bugs, you can install it. Also, don't forget to back up everything on your phone including your photos.
As for a release date, there is no official one except that it will be in 2015 after the release of the desktop version. I would expect it to be in October-November timeframe but that is my guess.