Here is a quick size comparison of the P30 series (sorry for the crappy pics, best I can do right now). Honestly, since I got the P30SK, I'm starting to question why I have the P30. I'll probably carry the SK more than anything else. The P30L was/is just for shooting some matches at my local club, and plinking. It's way too big for me to carry regularly.
I've been shooting and training with LEM HK's for close to 15 years now, I strongly prefer the paddle magazine release, use your trigger, or middle finger and it's much faster, for me anyways than a button release. I wouldn't want to go back. All the guns are LEM.
I also strongly agree, train, and shoot what you are going to carry, don't mix and match trigger types.
The P30 series, SK on top, P30 in the middle, and P30L on the bottom.
P30 and 30L, with the VP9 in the middle.
The gun I wish they would build (besides a single stack), is a P2000 with the P30 grip.