OK- I've got 4.5" in bi-tone 9mm and Ive got about 700 rds through it. I love the sights on the 5.25 and,it will cost you $250 or more to get them. Dawson Percision is what SA uses and sight pullers have been broke trying to remove them.
If you get 4.5 and later want to do a change out, that's $160 but rear sight will not be seated into slide like in a BoMar cut on 1911. I don't like the hole in the slide but if it helps w light loads, so be it.
5.25 is a superior range, Tgt, competition firearm. If you want to carry, the 3.8" is hard to beat and you can use full size mags. Wee bit more muzzle jump. The SW M&P line is also worth a second look. I like a longer sight radius - preferably 6" which is expensive for an entry level gun.
The cost to upgrade is high, so why not get it the way you want it right out of the box!