The OP also doesn't mention--and may not be aware of the differences--whether it's the older/original large frame Vaquero or smaller "mid" frame New Vaquero. Only the New Vaquero is in "regular" production, starting appx 2005 (?), though special distributor runs have been (and may be currently) done of the larger model.
All New Vaqueros (note capital N) EXCEPT the .44 Special will say "New Vaquero" on the frame. However, confusing things, Ruger (and now many of its distributors) is just using the term "Vaquero" in their online and hard copy literature for Vaqueros, old and New. SO, whenever inquiring about .357 or .45 ASK which frame.
IMO, the smaller frame is more than adequate for the .357, is a tank whether Bisley or regular plowhandle, and the large frame more than needed, even overkill for most folk...And the large frame for the .45 "needed" only if intending to shoot "heavy" or "hot" and particularly "Ruger only" loads...although some prefer the larger model, regardless of caliber, "just because"--grip shape and size, extra heft, etc.
Functionally, the New Vaquero (and its .357, .44 Special and .45 flattop Blackhawk stablemates) improve upon the original, larger model in having the new cylinder (chamber) aligning pawl, stopping each chamber precisely for loading or ejecting.
I'll let others dicuss the specific merits of the calibers/cartridges themselves as I don't CAS. However, regardless of use, most would agree the big bores balance "better,"and related, certainly weigh less. IMO, regardless of use, and especially if getting a .357 for an all-purpose firearm, keep the barrel length down to 4-5/8" or 5.5" max, final choice maybe depending on the user's priorities: sight picture, the longer usually favoring--versus handiness. That gun can get a bit hefty on the hip in an afternoon of trailin'. With the "little" .357 holes--seven of 'em--there's a fair amount of metal in the gun. OTOH, as a general statement I will say the .357 is an awfully versatile gun, and can shoot milder and cheaper .38s for target and plinking.