I am new to this forum and new to H&K pistols. I owned a usp 40 at one time but traded it off because I did not like the double action first round shot. Hk caught My interest, very recently, after a local gunstore owner showed Me that it could be carried cocked and locked as a single action first shot. (I was amazed at this attribute) and now I want to get My hands on another one. I'm very impressed by the ergonomics of the new P30 but like the set up and action of the USP. I have several friends that own gunstores and they have warned Me of the horrors of HK customer service (stating that "it's the worst in the business.") But they also tell Me that HK's are so good that they rarely ever go back for repairs. I am very interested in the USP 40 compact but My questions are; What are the differences in variants? Glock utilizes a tenifer finish, xd uses melonite and the M&P's use melonite over stainless. What is the make up of the HK slide. I guess I could use a general introduction. (I've looked on HK's site and I found that it wasn't super informative.) Thanks in advance for the info!