I have both. Roughly 500 rounds through each of them and at least one IDPA match with each.

If you told me I could only keep one of them it would be difficult for me to decide which one to give up.

They bought have their pros and cons. VP9 magazines cost about twice as much as I typically like magazines to cost. Also, some people don't care for the paddle type magazine release on the HK because they aren't used to it.