Just played with one at the store and the Pen is not different in a better way from my Note 3. If I liked how that worked I'd be on a 4 now. I didn't like how you have to press just to write and not just to get thicker lines. I lift a little when writing an it would not get everything. Also, when I kept even pressure and ran all over the screen it would cut out and come back it. Mostly cut out in the middle of the screen. Is there a way to adjust the needed pressure of the pen or was that just an issue with those to floor models? I guess it could just be something to do with S Note too.
Forgot to check if you can switch it over to ART for ready before request processing. They didn't allow it with Kit Kat on the Note 3.
I was hoping for 64bit, but hopefully next year. A better pen, ART architecture, and the little boost in processor. With the pen as is I might stick with the 3 or slight chance of trying another brand. Apple has a big phone now, just kidding.
I tend to press quite hard when writing with a normal pen, so I haven't had the issue you mentioned with the floor model. I'll attempt to write a bit lighter later today and see if I can duplicate it on my brand new model. I'm not aware of a setting for the pressure required. The first thing I do when I get a new device (after logging in and starting app downloads, of course) is to go through ALL settings, so I'm fairly sure it's a case of it not being there and not me missing it.
As for ART, yes, it's possible to switch. My phone is currently optimizing apps after having restarted itself to switch to ART. Thanks for reminding me!
If you have other questions about the phone, feel free to ask and we'll dig deeper for you than you'd have time for in the store. I'm still loving the phone, but it's such a switch coming from the s4. It's definitely less of a switch for those of you already using a Note device.
EDIT: For those who want to switch to ART, here's the guide I used.
Samsung Galaxy Note 4 Change Runtime from Dalvik to ART
Long story short, enable developer options by tapping on build number 7 times, go into developer options, tap on "Select runtime system," and select ART.
The phone will reboot to make the switch and then optimize apps. Takes a while to optimize all 427 apps I have, so I'd definitely recommend doing this before installing all of your apps if you've just gotten the phone if you want it to be a bit quicker.