I think it's made things much smoother and I actually waited until I had the Note 4 for about 2 months before I switched. I love it... except for when rebooting the phone - it takes forever to start back up and uses a "bunch of battery" on the restart. However, mine is on all the time so that doesn't bother me much!
I just switched to art the phone got real hot but after it cooled down it seems to be running good all the apps working haven't did a reboot yet but so far it's running great
Thanks, all. Switched to ART late yesterday and if there's any difference I can't tell yet. The phone was already a beast, so I didn't really expect a speed increase.