I have a redhawk .44mag it has built in scope mounts on the barrel rather than the frame and came with the SS rings pictured on the super, but these are an option on the redhawk AFIK, and it can also be bought without them.
The grip frame is different as is the lock work.
The gripframe is finished on the red hawk and much better looking IMHO and you can have the backstrap and frontstrap exposed. The Super redhawk, is like the sp101 in that the entire grip area is like a big railroad spike, and must be covered with a total wraparound type of grip.
On the redhawk there is only one spring (if you dont count the tiny handspring) So tuning it requires using a wolf spring kit, IIRC I put the 13 lb spring in mine (kit has 12, 13, and 14 lb IIRC and the stock spring is like 17 lb). The super redhawk has a couple of springs a main spring and a trigger return spring, so the trigger is more tunable.
I like the balance of the redhawk better, so that is what I bought, also I felt the .44 mag 300 grain bullet loads it can handle would be as much recoil as I would want to handle in a handgun.