Got a chance to play with an S4 for an extended time today. Samsung had a launch thing at the at&t on Michigan ave in Chicago. I was about to hit on the Samsung promotion chick, Lol. Also some of those at&t sales associates were gorgeous.
Anyways, I was shocked on how nice the phone felt in my hand. It's easier to hold than my naked galaxy nexus and I don't think that I'd drop it easily at all without the case. The screen looked great and setting it to the movie type of screen made it look similar to HTC One colors. Both screens are great and you can't go wrong with either. Just because this phone isn't made of metal doesn't mean that it's shit at all in how it feels. It just felt really good to hold and wad very slim. Additionally the big screen gets all your attention so you kind of forget about the rest of the phone since you know, this is where you're actually doing everything. When using it was fast, smooth, and it had no lag.
Compared to the HTC one, naked, this definitely felt better to hold IMO. Some review mentioned how it was the most comfortable 5 inch phone to hold and I'm starting to think they're right.
On top of that, I'd plan on getting a few nice minimalist cases. All you're left with is the big beautiful display on a phone that's a good size and easy to hold for its size.