Do it for the money, the ranks just happen; for me the game had just begun once I got to 120..and as far as content goes both GTA IV and Red Dead got more support than they ever needed. Rockstar has a propensity to support their most successful titles and this is thus far the record holder in addition to being their flagship game...on one hand I don't have high expectations; on the other I would be very surprised if they didn't add more than enough content.
I'm just a couple ranks from 200; while its mostly about cash for me now, I went through a bit of a crisis around 150 where I thought I should stop caring about rp all together as well as aim mode, difficulty and just go where the wind takes me,..however over the ranks I've changed my mind completely and into the 190's I only play free aim with hard difficulty. I've been hearing about cheater bans, so hopefully the fake ranks are noted in the automated sweeps, because being associated with that gets old when you are legit.
The good thing is that now if you see someone with a level above 150, you know it's more than likely a legit player. Just looking at someones stats would also confirm that.
Before the big money and RP maintenance that Rockstar did, it was fun messing with players who were clearly RP glitchers. Many a mugger was called and the 'off the radar function' was abused by me to sneak up on them. My baseball bat and shottie were having the time of their lives lol
Sometimes i do miss all those script-kiddies to use as target practice