Anything except SD9VE. A good pistol needs a crisp trigger.
I narrowed it down to those three bc they seem to be the budget 9mm's that are actually decent, available now, spare parts etc...
I don't think any of them get bad reviews really, all under or at $400, sometimes even lower... I know the SDV9 is supposed to have a heavy trigger but some ppl seem to like it.
I am new to shooting and I chose the Canik tp9sa. Like others have mentioned, the trigger is really fantastic. It breaks clean and the reset is tactile, short and audible. It's trigger is much better than the m&p9 and the ppx IMHO. Haven't shot the SD.
I've been shooting a Walther PPX range kit (with 3 mags!) which I bought for $419+tax (of course) from Tenda a few months ago. For the price I paid it's the best pistol I've ever had. The trigger is absolutely splendid. Very accurate up to 25 yards. Field stripping takes just seconds. Excellent overall quality. It's a large pistol though, good for people with large hands. I have large hands and it fits me superbly, like a proverbial glove.
If you can get a PPX range kit for under $500 do not hesitate.