Well, I would check out the Known Issues thing for each build which has some what-to-expect stuff.
But personally, I have a 640, which is similar internally, except in size.
The last build was "eh." It had features, but was too unreliable for me. Some people are fine with being in the Insider program, some aren't. Also combined with how some people have a graceful experience while it's less pretty for others depending.