This was one of the tablets I short-listed for a customer. I have a Nexus 5 phone. IMO, mine is more responsive than this tablet (I can't think of any points or times where I've considered mine to lag), the 8.4 seemed laggy at times, I can't say I was particularly impressed with it.
Based on my experience with the N5, I'd go with a Nexus tablet (if I wanted a tablet) I think unless I heard some very conflicting reports about it.
The other thing I noticed was the poor content scaling on the Google Play Store, overlapping text when you click on an app that you want to read more about. If I had authority in Samsung, I would have stopped it shipping until that issue was fixed, one way or another (Google's fault?).
The screen auto brightness was also odd. Initially when I picked it up, the screen was so dark that it was barely legible (darker than my N5 if I manually set brightness to zero), and this was in a dark room. It recovered from that within a minute or two, but it was still weird.
I'm surprised by the comments of the 'amazing screen'... what are you used to then? I would use the N5 as my yard stick for comparing screens with other mobile devices these days I think, and I can't say that the Samsung screen seemed amazing. Perfect decent perhaps.
16GB for Apps.... Not an issue for me.
Yeah, I was thinking that when the person you replied to was saying that 16GB even with the option of a MicroSD card wasn't enough!
At the time of posting this I've only browsed the first two pages of this thread, I don't have time to go through the rest right now.