Yeah the 65 is pretty much my go-to lens, it's so versatile. You'll definitely love it. I also have the 45P and the 30, but combined I don't use them anywhere near as much as the 65.
I don't use the control grip that often (I seem to prefer the 'naked' camera), but I found it most helpful in colder weather while wearing gloves. Overall I don't really mind the ergonomics for waist-level shooting. It's certainly a beautifully-made accessory.
What I really wish Hasselblad would do is get their AE lock function properly sorted out, instead of the wonky way they currently have it. I think they are past due for a firmware update.