I bought a G15 last November, but when I decided to replace my Cobra irons a few months ago, I desperately wanted Mizuno - love the look of them, but when I went to get fitted, I just couldn't get them to perform for me. I only booked a Ping fitting (prior to the Mizuno fitting) to act as a comparison, but they were awesome from the start. I haven't regretted the purchase at all as my game has gotten better and better since I bought them.
Just about to add the G15 3 wood to my setup - have played it on trial for a couple of rounds and it is fantastic. The only Ping I couldn't get to work for me yet is the hybrids, need a bit of range time for them.
Won't be going back to my old anser putter though, the Scotty is staying in the bag.