IMO, the .44 is more versatile in terms of power. Trail Boss or Cowboy .44 loads can do anything the .38 Special can, but there isn't a .357 load that can approach a full power .44 Mag. The .357 is more versatile in the variety of weapons. The .357 can be used in smaller and lighter revolvers than the .44.
So, if you're going concealed you're looking at 5-6 shots of .357 (equivalent to 9mm out of a snubbie) vs. 6 shots of .44 Mag (equivalent to .45 acp out of a snubbie).
That's the first consideration, will you be using it concealed? A 5-shot .357 is significantly smaller than a 6-shot .44 mag.
If you would limit me to a single revolver I would pick my Model 29 engraved, hands down with the Trail Boss a close second. That said, my first revolver was a .357 ported snubbie (actually a pair) which I still love (you haven't lived unless you've shot a .357 Mag ported snubbie in the dark
).
With a .44 you can use a .44 SPL which is similar to a .45 ACP up to a full-tilt .44 Mag loading. But you're usually limited to 6 shots.
For .357, most folks use a .357 mag snubbie. This translates roughly to a 9mm. For concealed you're usually talking 5-6 shots. If you're packing full size then I would recommend a S&W TR8 (which, sadly, I never had) or another 627 derivative giving you 8 shots of .357 mag.
Myself, I like the .44 mag world:
Here are two of my many .44 mags, a 629 Trail Boss over 629 Custom Shop:
The best combat revolver I have is my engraved model 29 (quarter-sized groups at 25 yds), here shown with a 329:
Here are some of my .357's, a 627 Miculek and a 686 custom hunter my friend built: