If you believe the hype from sports media outlets all over the country, Thomas has been Bush-whacked as the starting RB in Miami.
Don't believe the hype.
You would have had to be living under a rock for the past three years to believe that Reggie Bush has the capability of being an every-down back. The second overall pick out of USC has made it very clear that he is effective as a hybrid RB/WR, mostly catching passes out of the backfield.
However, he's extremely limited as a go-to back. He averaged 3.7 YPC with the Saints, on a team where backfield mates Pierre Thomas (4.8 YPC) and the studly Aaron Stecker (3.9 YPC) were much more effective. When switched to his hybrid RB/WR role in, Bush became a much more effective back (5.6 YPC). Bush is built to be a pass-catching, hybrid back.
Thomas is built like a monster truck. At 6'1", 230 lbs, the second-round pick out of Kansas State has the physical size to handle the role of an every down back, and is especially suited for the goal-line role that is the gold mine of fantasy value. Then why has his value been crushed by fantasy analysts? Because of "a poor preseason." These same analysts who tell us not to pay any attention to the preseason would be best served to listen to their own advice. Preseason play isn't indicative of in-season performance (just ask Michael Vick last year).
But even if you believe somewhat in preseason results, the strangest part about this whole saga is that Thomas hasn't actually had a bad preseason. He rushed for 52 yards and a TD on 12 carries in his second preseason game, a solid performance from a rookie RB. In his third game—which earned him flack from both local and national media—he carried the rock seven times for 16 yards. Unspectacular? Yes. Horrible? No. Here's the best part: In the same game, Reggie Bush carried 5 times for -1 yards. Yet D-Thom gets the negative press.
Bottom line: Don't believe in Bush, and don't believe the analysts. Go against conventional wisdom and draft Thomas at a steep discount. Acquire Thomas at a low price and you could be laughing your way to the playoffs.