I bought the 2009 AC30 with the IPT12. I will say that this ski does great on the groomers - especially on hardpack/ice. I have had no problems with chatter on ice - put the ski on edge and it rides like a rail. Also the skis are very stable at high speed. This is a great groomer ski and an occasional off piste ski (90/10). However don't ride the tails or you will pay for it dearly - these skis will launch you. However keep forward on the tips and they will ski through anything.
I have seen a number of stores offer the IPT11 - probably not a big deal. However if you are an east coast guy and run into skating rinks from time to time, I think the IPT12 will be worth the extra 60 bucks (IMHO).