ok more:
didn't take too long to download due to having 60mbit home internet, but still a good while. the install itself didn't take to long, the first boot "optimizing apps" took much longer, said a had 344(!?!?) to do (how many background app does this phone have? I know I've only installed a fraction of that). First boot was quite laggy and eventually the screen fully locked up even though the buttons still made the drop noise and vibrated, said it needed to update google play services (why didn't the version needed for 5.0 comes with it?). After a battery pull the second boot was bit smoother for a little while, still needed the google play services update (didn't make it this time either) though speed got worse and worse to the point where apps hanged the OS (when a pop up about com.android.system not responding appears it's probably dead). During the third boot play services finally manages to install, and has since ran pretty stable no major crashes since.
advice: even after it's done booting the first time let it be till google play services fully updates (or the phone crashes) trying to not use the phone at all. Might have less trouble that way.
good: love the new lock screen, much better then kitkat, didn't care for the fact that Samsung completely changed it from stock to something rather useless. I like being able to see my notifications on the lock screen and even scroll through them with it locked (A first? don't remember even being able to access notifications on any past phone with any type of security on. love the new Recent apps screen so much better then anything I've seen before, alos very fliud and fast when moving through them. love the bouncey non-static card like nature of the notifications, rather then being a dull single colored screen, these act like a stack of cards when you have a bunch. Samsung wise things are much brighter, the black of the settings menu is replaced with white. The priority sound, calls and notifications looks rather interesting.
so while yes, it's not exactly ready for the mainstream currently i'd say, I do fell like once the kinks are worked out (hopefully) this will be much better then kitkat.
worth it to install now? maybe, I'd say it it's very much YMMV, it might work good for you it might be a total pain. If you want something rock-solid that works, I'd say wait cause this isn't yet. If you want something that is I think better then 4.4 and don't mind a few (or maybe many) issues, then it might be worth it.
(I think this might be the longest post I've ever written on here)