Do you care about decocker vs safety at all?
If it specifically for a range gun, the SP-01 will be the heaviest (and probably easiest and most comfortable to shoot), followed by the 75B and then last the P-01. If I had an economical choice between the stainless and non-stainless, I'd pick the stainless.
9mm is the most expensive of the "big" calibers, but much more expensive to shoot than .22 of course. However, I think it's a lot more fun too, especially if you can get to a range that has steel targets or have the opportunity to try IDPA (tons of fun to do the courses and pretty cheap too!).
However, if you ever plan on CCW, I'd go for the P-01 (smaller, lighter) though I personally use a 75B.