I'm going to assume you're taking your RB2 in round 5 based on these players. If so, that means you have a stud RB1 in round 1, two solid WR's in rounds 2 and 3 and then a BPA in round 4 out of QB/WR/TE. Anyways, I like Felix as well, he can do it all (run, catch, goal-line, etc). All of the other guys have more ?marks imo.
Felix Jones - When the owner says you are having the best training camp of anyone on the team the whole shark pool sees blood in the water. Every year there are a few breakout players (Peterson, CJ2, Gore, Rice, Charles, Bradshaw, Foster, DMac, etc). I think Felix is that guy with the stars aligning for him.
Ryan Mathews - RBBC and losing 3rd-downs and probably half the TDs
DeAngelo Williams - Who knows how this offense will look when the season starts. Could be good and surprise, or could be a train wreck. He's going to share with Stewy and Goodson "could" steal the 3rd-down carries after his performance last year. I'm not touching this situation unless it's insane value. Honestly, if I had to choose between he and Stewy, I would take Stewy 3-5 rounds later expecting similar production.
Mark Ingram - I like Ingram, he'll get a ton of TD's in this offense since they'll have a lot of scoring drives. PT is looking good though, so it could be 50/50 with Ingram the 1st/2nd down back with goal-line while PT getting every 3rd series and all 3rd down work.
Knowshon Moreno - I live in Denver, and I just don't think Moreno is going to be able to hold McGahee out of the starting lineup. He's not big enough. He weighs 200 lbs like a lot of other elite backs, but the difference is that he doesn't have their elite skills. My opinion is that McGahee rushes for just over 1,000yds and double digit TD's leaving Moreno for 3rd down duty and few extra carries between the 20's.
I'd throw Wells into the mix here, and I'd probably take him over all of these guys except for Felix.