I have a usp40c, its physical dimensions are the same as the 9, just a little heavier. I have never had any issues concealing with an iwb holster. Both guns use cold hammer forged barrels so it isn't recommended to shoot lead so in that way they are similar. It is my opinion that the hk is higher quality than the glock, each generation of the glock has made improvements and had its teething pains (recalls) where the hk is basically the same gun since release. I do not like that with the glock you have to pull the trigger to release the striker before disassembly, many gun owners have had NDs because of the field striping process. I also like having a real safety on top of the "safety features", where the glock has documented cases of discharges because something snagged the trigger when being holstered. The buffer system on the hk compact is not as effective as the system on the full size but makes the recoil manageable to the point that my wife handles the 40 without issue, the 9 will be even more so, on that point I can't speak fire the glock.
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