I got the 12* and have a couple of rounds under my belt. Bought the club due to erratic driver play which didn't match up with my relatively consistent swing using fairway woods, irons and hybrids off the ground. Like many, I resort to just giving up potential distance using my 3 wood at times.
My average driver carry distance is 240 yards, 3 wood about 200-210. I bought the mini hoping it would give me something in the middle that I could tee up lower and would be more forgiving of my sometimes steep swing and I could groove the same setup as the other clubs.
I think for the right player TM is on to something here. Hit 23 of 28 fairways last 2 rounds and off hand I'd say it's only about 10 yards shorter on average than my driver which is a 50-50 proposition at best.
Hit off the deck a couple of times on wide open par 5s and was rewarded with long, low bullets. The sole seems to interact off a nice flat lie fine but I'd hesitate about hitting it out of anything else.
Nice bonus is it helps lighten the bag. I took out just 9 clubs, the Mini,a 20* hybrid, 6-pw and SW and didn't need anything else.
Also demoed the Callaway Deep extensively on the launch monitor and while I thought it might be potentially longer, the larger head of the mini suggests it may be more forgiving and confidence inspiring on course.
Good luck!