I think either guy is a viable flex option but I'm not expecting much more than that this year - in a PPR league, I'd rather have Hightower, otherwise, I'd take Beanie. Beanie seems to have more talent, but Hightower has been treated like the starter this preseason and, honestly, has looked a little better this August. Plus, Hightower is 24, so while I think people easily see Beanie as a young guy with potential to improve, they forget the same is true of THT. I think they will run significantly more than they did last year, but it is also pretty clear that overall the offense is going to be less effective. Another to factor in is that they have several great matchups for RBs this year, so either guy could be a good option to have in a flex-by-committee or RB2-by-committee type of situation.
I expect both of these guys to get some more yardage, but don't expect an increase in TDs...if anything, those will drop a little bit. I also think this will be very close to a 50-50 split, but that's more based on a hunch than anything else.
To be concise, I like THT at his ADP, and I think Beanie is going a little too early at the moment, but I'd jump on him if he falls much past the 6th round. I think 1000-1200 yards from scrimmage and 5-8 TDs is a realistic projection for either guy.