I'd say go to a store that has both, look through them, play with them a little, and decide which one you like best because you would really be splitting hairs to find much difference between the two in both durability and optical clarity. The Redfields are really new so you're not going to be able to find too many people that will testify to durability, but they are made in the same facility as a Leupold VX-1 so they should be great. The Redfield warranty is also the same as Leupold which is as good as it gets. The real advantage to the Prostaff is that they've been around long enough that you can find some deals on new scopes on ebay, or pick up a used one at a really reasonable price. You might also consider a Sightron S1 or a Weaver Classic V or 40/44. I've got both of those as well as a Nikon and they are all great scopes for the money.
Jake