Well, fired it up today, and played straight through to the 5th chapter in one sitting, never feeling like 'would this cutscene end'. Rockstar did a killer job making it all seamless.
360 controller works best for everything but aiming, so switched to mouse/kb. Too bad hardcoded keys in the game (enter, home), as an arrow user are prime keys I use, so I'd knock off a full letter grade just for that... why games from ten years ago let you bind whatever the hell you want, and games cant do that today supersedes my gripes about cutscenes.