I think that with this build they pushed a lot of new features, and with the next build they'll tweak them more. We got a lot of new toys to play with, but I think the previous build were more reliable and mature. This is, for me, the first Windows 10 build. The previous ones were 8.1 with tweaks, which was good for daily use, but that's it.
Sadly, I don't trust MS to actually use the feedback. I'm using W10 daily, and I do give feedback via the app, but I don't think it'll matter. The "One Drive" placeholders issue made it clear.
I think it's a new Start Menu, not like the one in 8.1 and that's why it can't transform into the start screen. Maybe it'll be able to do so in later builds, don't count on it. Count on a 3rd party utility to add this feature later on
So my laptop is barley working, all of the my start screen layout was gone after the upgrade to 9926, store is buggy and more Win32 apps are getting killed (Calc), but I enjoy it. Beta testing is fun, it's just too bad what W10 is shaping to be.