Just got through the Smuggler's Hideout. Pros/cons I've noticed so far:
+ The upped framerate and improved FOV are really nice, and work together to amp up the tension.
+ Gameplay feels way smoother than the original generally, probably due to the higher framerate.
+ There's a generally sharper look since the textures have been mostly redone and the resolution is higher. The original game could get a little fuzzy in places, and details pop a lot more now.
- Some of the effects that got a lot more work in the original weren't recreated 100%, like the water effects that have been discussed to death in this thread.
- The biggest problem I've encountered is audio issues. Sometimes a couple words of dialogue will repeat, either during voiced scenes or audio logs. And in other cases enemy chatter pops up before I can hear it, or even worse when the enemy's in the other room and they shouldn't have noticed me yet. This happened sometimes in the original, but followed me everywhere in Neptune's Bounty in the remaster. Really immersion breaking. (2K Support suggests actually clearing my cache between plays, which might help. We'll see.) The audio's also a little less balanced. The dialogue seems a bit too quiet sometimes.
- The other problem is that I find myself triggering accidental Eve injections when I mean to hack things mid-jump instead. This happened very occasionally in the original (the timing window is pretty short), but happens every time I have to jump to hack a camera in the remaster.
Assuming the audio loops get fixed with a patch, I don't see why this wouldn't be my primary mode of playing these games from now on. Even then, they're not a total deal-breaker, especially since I'm already familiar with the game anyway.