I had one that I really liked.
It was fun/easy to shoot, and very accurate.
I would think it would carry well in a IWB holster.
Given the small size, I would think it would carry easier than a 1911, but I haven't tried.
The only reason I traded mine, was because I wanted to pocket carry.
I got a PM9.
I love it too!
But, every time I pick up a MK9 at my dealer, I drool a little.
There is just something about well made, all steel guns.
(Sorry, drooling again.)
In the end, I decided that, if I was going to belt carry, I would go with a bigger gun. (S&W 457 - .45 acp)
For pocket carry, the PM9 is hard to beat.
I can't say anything bad about the MK9. (Other than the weight.)
If you want carry on your belt, it is an excellent gun, and the "9" is not too shabby for defense.
For a fun range gun, the MK9 will work, but I wonder if a full size K9 would be even better.