I just got a '16 Kirby last week. IMO it's a fine bat. I have about 6 swings on it and 4 of those are HRs. Not weak ones either, but BOMBS. The '16 seems to have a slightly softer feel than the '15 and definitely feels hotter out of the wrapper. The '15 just seemed like it had a less forgiving barrel overall. Stiffer and more likely to vibrate than the '16.
All the swings on the '16 are with .52 balls. It literally webbed from swing one. The webbing seems very superficial though and I'm not worried about it.