If it's for her, let her pick it out. It'll need to fit HER and be comfortable for HER. You don't choose her shoes, don't choose her firearm. Bring her to shop and let her see what SHE likes. Let HER handle different models. Her gun, HER decision. Never know, she might prefer a revovler over aan auto loader in which case the whole .357 sig/9mmthing it's almost moot.

The .357 Sig chambering can be snappy I think. I've shot it in a P239 and in a CZ RAMI. Shot very good but it's got a good snap to it.