Im sure it's a huge overhaul than the note 4....... I had in December. That thing is a brick of lag city. Oh yeah, the camera in that is complete garbage as well. Only thing good about it was taking photos of sunny days with no movement. If you have kids or pets, forget about even taking a decent photo. As of the S6, to me is still more of the same laggy touchwiz from what I've seen. I think this phone is better than the Note 4 but it's way over-hyped.
If all your used to is android, the lag may not seem like a big deal to you. Not going to argue about software on each, it's obvious iphone's software is better designed for their own hardware.That's the issue with android, too many different manufacturers to get it to run right on every device.