I've got the 4 5/8" barrel .357 in polished stainless, and I love, love, love that gun.
People will say, rightly so, that the .45 balances better since there is so much extra material in the .357 version.
That said, I don't reload. I like the ability to get a wide variety of ammo for my needs. Mine shoots point of aim at 15 yards with most loads which is probably as far as I would pop off a shot with a handgun. It's my camp gun that either rides in my pack or truck or gets tucked into a shoulder rig on a hike where I feel a full size revolver is necessary.
I love single actions for outdoor duty because they are so robust and I shoot them more accurately. I rather prefer the non-adjustable sights on the NV over my BH simply because they can't get bumped and buggered. I generally pack a box of 50 rounds of misc load out. Usually 6-12 .38+p, 6 snake shot, and the rest .357 soft points.
I DO plan on getting a .45 if ever start reloading, but right now, I just won't get nearly the performance out of high dollar/harder to find CAS powderpuff loads in .45 Colt over the .357.
Edit to add: Also keep in mind that the .357 version of this gun is a TANK. To my knowledge, and please take it with a grain of salt like all things on the internet, there aren't the restrictions of firing hotter rounds through the .357 that there are with the .45 Colt version. The .45 is plenty tough, but you don't want to shoot "Ruger Only" loads through them. They are quite a bit thinner and lighter in build than the Black Hawk. The .357, though, it's pretty doggone robust all over. Probably not Black Hawk strong, but it's a chunk of steel to be sure.