Since you reload, I'd say any are good.
I own a SRH in 454 with the 7.5" barrel, and I have a 460(Magnum Research BFR 10" barrel).
The SRH is a chore to shoot with fully loaded 454s. It is downright painful. After a cylinder full, I can feel pain in my wrist for a good half hour to an hour afterwards. To quote someone else who I let shoot it, "I was wishing it was over after the 3rd round".
The 460 is more fun to shoot, just because of the platform. The BFR is so heavy(mine's about 5.5 pounds with scope) that it makes the recoil less snappy than the SRH. But it gives you a big push for sure.
Being that the Smith is ported, that should make the 460 fairly tolerable even though it's lighter than my BFR. I'm not sure about that short barrel though. You just won't be getting the true potential of the 460 with that length. A longer barreled 454 will get nearly the same velocity. HOWEVER, the fireball and shockwave that thing will put out will be impressive! (if that is what you like)
Do not be sold on the 460 for the fact that it can shoot 45 Colt, 454 and 460. I did quite a bit of experimenting with the 45 and 454, and accuracy with those ranged from fair at best to dismal. I only shoot 460 brass in mine now, but I often times load them way down. For example, I shoot 255gr lead bullets anywhere from 1,100 -1,500 fps for plinking. For hunting loads, I have 240gr Hornady XTP mags, going a bit over 2,000 fps. So you have a huge range of what you can do using 460 brass, and accuracy doesn't suffer.
So in the end, since you have a 45 Colt and you reload, I say go for the 460! It is a really fun caliber to handload for. Although if it were me, I'd get the XVR with the 8" barrel. Seems like a waste to shoot 460 out of a 5". But that's just me.