They are both good backs. To maximize both of their abilities the best, Beanie should get the 1st and 2nd down carries, and TH should be the 3rd down back. I think having them both in a solid role will help them perform even better. One of the things I've noticed is that TH has had some ENORMOUS holes to run through, just huge. Shane brings up the long plays that he has, and if you look at them those are probably the biggest holes we've seen all season...maybe decade. BW doesn't see those holes. Reason being, IMO, is that with TH in you have the run/pass mentality and the defense can't key on TH, and he makes them pay. When we bring BW in, teams game the run and focus on that. If BW is in for most 1 and 2 downs, teams will have to back off more. You saw a bit of this with him getting the bulk of the carries against SF last night, with better holes and a 5 ypc against a VERY stout running defense.
TH is great with the ball on the catch, and is great...yes great at blitz pickup. He gives 3rd down lots of options, and BW on 1st and 2nd gets better looks at defenses who don't think "here's beanie, they're running." I feel that is where we are going, and it's damn close to happening.
These two backs are good, tough and talented. I prefer BW, but I respect the hell out f TH and his work ethic. I love the combo.
Both of those fumbles were on solid licks, and fumbles happen. I can't fault either of them on those two. They sucked, sure, but good defensive plays on both.