smoke'n it does not matter much what you carry so long as it goes bang. Also don't take what some gun shop sales person tells as the gospel ether. Most of them are like used car salemen!!
Ha! Funny you should say that! I AM a used car (and new car) salesman here in Utah! No offense taken though. I've seen, over the 10 years in the business, that most buyers leave their ethics at the curb when they come in to see me for a car.
The gun guys weren't trying to sell a Springer over a Glock. That was me. I just wanted to hold and shoot a few with their rental program. I scooped up lots of information on line before buying. I believe you are right on their likes and dislikes - just like here, right? Maybe they make 10 bucks more on one gun or the other. But, the guys I've worked with don't try to put me together on their preferences. Maybe I'm just lucky.
As to IWB.. I'm all for that, and carry my XD45 Compact with 5" bbl IWB. I just have a crappy holster with a sloppy belt clip, so it's a dicey affair...!