All Redhawks (RH) have a grip-shaped frame, so the exposed backstrap is a given. The Super Redhawk (SRH) have a post that the grip fits over, permitting a padded backstrap and a wider range of grips. The RH, like the Security Six, has a single spring lockwork with a long DA pull. The SRH is like the GP100, and smaller-scaled SP101, with a two spring lockwork - and similar grip studs.
My first DA revolver was an early new 7.5" .454 SRH, which I loved. My first S&W was a new 625MG (4") in .45 Colt, which quickly outgroupped the SRH with .45 Colt. I added a new SS 5.5" .45 RH several years ago, ordered along with another one for a friend - just before they were dropped - and put on closeout... we paid a lot for them. His had a warped frame - and he got another new one, which he sold. Mine had just too many QC issues - including burst casting bubbles between the cylinder bore exits. Both had consistent exit bores measured between .4520-.4525"... that problem was 'fixed' before they dropped them before. I kept mine for some time, selling it finally ~ a year ago... I had acquired a second 625MG in .45 Colt.
Both 625MGs would group better with 255 gr LSWC/850+ fps at 25 yd than the RH, much less the SRH. Of course, that SRH with 240gr XTP .454s (2k fps) was the best grouping - 1.5-1.625" at 44-50yd, scoped (Weaver 2x28), from sandbags. It was maybe 6+" with .45 Colt Cowboy Loads at 50yd - 4-5" at 25yd, while the RH was 4+", and the 625MG was 3+". The S&W grouped ~2" at 25yd with either 255gr LSWC or 250gr GDJHP ~840 fps, better than the RH. Also, the S&W ejected with never a problem, while the drooping RH ejector regularly slipped over the dimunitive .45 Colt rim, making reloading time-consuming. The trigger pull on the stock spring RH was long and often resulted in ftf's with my Federally-primed homebrews, while The lightly sprung S&W never had a ftf. The RH was a lot heavier, too.
Sure, the 625 cylinder, barrel, and frame is rated originally for .45 ACP - at least 22 kpsi vs the 'standard .45 Colt's 14 kpsi, but I won't quite run 'Ruger' loads in mine. I do like the better trigger, greater depenability, and assured reloading of the S&W - thus, the sale of my RH. No, I don't want either a 4" .44 or .45 RH - the SRH is a far better revolver - better lockwork, grip design, etc. A 4" SRH might interest me... I still know what to do to 'clean-up' a Ruger...
Stainz