that one thing i have noticed about H&K is they are priced almost to the moon!
I'll be the guy saying if you got the scratch (and can find one) go for it. There is a guy who shoots at the Poco range that has one. A very cool firearm for sure. It always turns heads when it comes out to play. I can't afford it so I have the BB gun version of it (which is as cool as I can get). Don't let the nay sayers get you down (or we'd all be running Norinco's and nothing else).
The worst part is when you look at the department prices those things are sold for...
Think 1000 or less for a UMP, 1500 or less for a G36 (probably less without the optic-carry handle version), I'm sure the MP7 is probably around 1200 or so, of course the last time I heard anything about LE Agency prices was a good 5 or 6 years ago.
But it's the same reason the USA has the high prices for Machine-guns (Or full auto's) with the artificial cap. In Canada there are just handfulls of the UMP/G36/MP7's and because of that the prices reflect that.