I haven't had many issues except the rockstar map on social club has different names for some of the landmarks from one of the lists I found and the dots are not always in the right area, sometimes a block or two away.
The funny thing is last night I actually fell through the game. I was going to pick up a film reel "The Big Carnival" and while I was running there I noticed a car and tried to turn around to get in (in case I didn't have it collected). When I turned to get into the drivers side, I went inside the corner of the house it was parked beside and landed in a gray oblivion that killed the game.
I will say that if you are going to work on collections, like landmarks, remember the game does not save on those or cars acquired. I haven't done any gold reels but the badge collection from gamestop will institute a save when you find one. If I've collected anything I always get a badge to make sure it is saved because I quit a game yesterday and lost about 5% of my collections.
Fun game but it does seem like it may be a little on the short side.