Let me preface this by saying that I'm a but under the weather, so that may be exacerbating things, but I just played a bit into the Favela area (Chapter VI?)... And I've come to the realization that the game is boring the shit out of me, either due to the "fun" being too infrequent or being outweighed by the game's niggling issues.
I found the Docks to be very tiresome and the closed corridor layout of a lot of the Favela areas only serves to highlight the mediocrity of the movement controls. Actually, I think I can confidently attribute 90% of my lack of enjoyment to the janky movement that has basically plagued every Rockstar game ever; only in MP3, it stands out a lot more because everything else is - for the most part - polished. It's a shame, then, that these polished aspects somewhat rely on smooth controls and that's something that really isn't given to the player.
Now, you'd have every right mind to rebut the above and assert that the jank is nowhere near bad enough to detract from everything else that you love about MP3, but the thing is, the core mechanic is just too simple. It's now bordering on tedium for me. It's the kinda game I'd rather watch someone play than play myself, because there's no denying that it is one panache-filled, visual extravaganza of a game, but that's not cutting it for me right now.
Again, let me reiterate that it's a GOOD GAME, but it's obviously not as amazing for some as it is for others (thanks, Captain Obvious).
TL;DR - I loathe the way Rockstar does third-person movement, basically.