I have an HK USP .45 and I love it. I would venture to say that you bought a fine weapon. I've seen it convert Glock shooters to HK lovers more times than I can count.
I have the HK45 and the HKP30. I love them both, They are really light weight and great shooters. I've never shot one with the LEM trigger. I'd like to do that sometime and feel the difference.