Well, from what Im reading, unless you are an absolute twitch gamer that likes the feeling of accomplishment against a greater foe after much trial and tribulation, then this game's singleplayer isnt for you. Multiplayer could be...
Well I am a twitch gamer, but I dont like having the odds against me, some gamers are naturally better at playing games than others. Im better than a lot, but there are plenty that are better than me also. This having the odds against you, like most open world games, the "bots" arent as creative or cunning, so they get innate boosts: knowing where you are at all times regardless of line of sight, being able to get head shots while strafing and running from 300+ yards with a none-too-accurate rifle, knowing where you are aiming at all times, these reasons cause me to stick to Mplayer, especially in sandbox style games (battlefield, GTA, etc). I wouldnt be suprised if the cops only chase players and completely ignore the bots (NFS did that, however GTA4 cops would assault bots, so Im not 100% sure, but again, GTA4 wasnt hard for the AI, some missions were just long and had overwhelming enemy numbers).
If the Mplayer aspect is fun and doesnt degenerate into FOTM car and build (everyone using a let's say the ducatti, all modified the same way for optimum performance), then Id consider it, but from seeing a lot of these comments, I feel as if the D2LOD mentality has seeped into more than just CS and WOW, and I think id rather beat my balls with a hammer than deal with smacktards in a 16 player bout.
In the end, I might rent this, but I doubt Ill ever buy it, maybe MC5. I think it's shameful that rockstar has neglected difficulty setting adjustment out of their last 2 games. That, to me, is a elementary mistake to make, like forgetting to program controls or graphics. Tetris had difficulty levels for christ's sake.