Get the HK, Great choice. I carry the USPc 12+1 .40 and it is a great weapon.
I like the .40, but the 9 might be easier to learn.
If you are serious about getting all the training you can, get the .40.
After some training you will be glad you got the .40....JMO
GET A GOOD HOLSTER.the difference is cc with ease or playing with you gun all day.