I agree with Kilt.
KWA makes great gas pistols that are nearly 1:1 with the real steel counterparts. Don't go cheap with springers.
If you're looking to get training value out of Airsoft, realism should be your biggest concern. With a gas blow back (GBB) pistol, you can train EXACTLY as you would with real steel instead of having to cock the weapon after each round is fired and creating training scars.
KSC and TM make glock GBBs.
And the price for this advice is a pic of whatever you decide to get.