Dear Ruger,
Please make the Super Redhawk with a full underlug.
Sincerely, The Whole World!
But seriously, I love the GP100, even the battered and abused range variant (the only one I have ever shot), super accurate, super sturdy....full underlugs are a requirement for double actions for me, and I like the "Combat" grip of the GP100 and the Colts as opposed to those of a Taurus (can't explain what I mean by that, not my term I had a salesman at the gunshop where I rented the GP100, I mentioned I loved the grip on the GP100 because it reminded me of the Colt Anaconda and he said they were both "combat style grips unlike the Taurus's")
So with that said I would say go with the Smith and Wesson for the full underlug.....or the anaconda as well.
...or heck, get all three