I have a VP9
I have a VP9 and love it.
I've been around the block a few times; I've owned 1911s, Sigs, etc before consolidating completely to Glocks for personal protection and gaming (USPSA and IDPA). I found that I liked having a standardized platform, and really disliked DA/SA. I never got into HKs because I found their triggers to be inexcusable for the price.
That being said, when HK came out with the VP9, I was immediately drawn to it. On paper, it is a gorgeous gun; HK reliability and build quality, thought out ergonomics. When I finally handled one, I had to have it--I even sold one of my Glocks to get it.
I have no regrets. The trigger is superb--my gaming Glocks are better, but the VP9 trigger gives great tactile feedback and in no way hinders accuracy or speed, which is the most I can ask of for a trigger.
The VP9 really shines in ergonomics; I have large hands, but for some reason use the small grips and backstrap. It feels like a very small grip, but for reason it works very well for me. It has also made even my 9mm and .40 Glocks feel bloated and large. My wife also prefers the small grip.
It is a very intuitive gun to shoot. The first time shooting the VP9, my splits were great; I have never just been able to pick up a foreign platform and perform at that level. I can also run the gun very, very quickly and get very acceptable accuracy--I can run it so quickly that it gets too hot for comfort within a short amount of time. That is great for a stock trigger, stock sights.
The charging supports seemed corny at first, but they really are cool. It is a solution to a problem that I didn't know existed. My wife loves them. I like the stock sights; they are fast and easy to acquire. I am going to leave them stock even though all my Glocks have thinner front blades and FO fronts. the stock VP9 are great duty and combat sights.
The magazine release is easy to adjust to. It is just as fast as the button release after one range session. It feels neither slower nor faster, but I have not timed it, so YMMV. I find it easier to use my trigger finger to activate it; I don't have to adjust or reaffirm my grip after releasing the magazine, which I sometimes do with a traditional button release. I like it. It has not caused confusion when switching between the platforms.
The biggest downside for me is 1) The 15 round magazine; it should have been 16+1 or 17+1 2) The lack of holster support. I have purchased a crossbreed IWB and Fury OWB that should arrive soon--we'll see how those do. I usually use Raven and Bravo concealment. 3) It is not as user serviceable as Glocks are, but I don't really need to modify it; I really enjoy it stock.
Here is a pic of some of my failure to stop drills at 15 yards. This was my first range visit.