Basically the same gun made with different steel.
Some say blued guns are more accurate and smoother. I’ve never been a good enough shot to see an accuracy difference, and my stainless revolvers are (to me) as smooth as my blued revolvers.
In carry guns, holster wear will slowly take the bluing off of a blued gun... and they can rust a bit faster if carried in a wet, humid/sweaty or sea-air environment a lot. (My 2.5” Model 19 lost bluing from being in a Bianchi shoulder holster too long) Stainless will rust, too, but usually at a slower rate.
I prefer the look of blued guns, but I like the ease of cleaning and finish-durability of stainless..
Both are great choices, I think you’ll never go wrong with ether one. My 4” 686+ is a former (temporary) duty gun I carried, I had it bead blasted so it was non reflective.
Stay safe.