Both great skis, I just had an awesome weekend on the Sultan's in Whistler. Fantastic all round ski. For the conditions I was in (2-10 cm on top of harder snow, lots of chewed up off piste), they were great. They really really like to fly down the mountain, really fun turn initiation. One issue I had was that they weren't easy to reign in if you just want to cruise. The little soft snow I did find, they handled very well.
I skied the Monster 82's last season and have skied the Peaks twice this year. The Monsters were my go to ski until I picked up a pair of AC30s which just seem to suit me perfectly. They were really great in soft snow for only 82mm and, they just blast through crud. Very powerful, damp ski. Likes to be pushed hard. And, I found that I could always get a good feel for the snow on hardpack.
I spend a lot of time in the trees and I appreciated that they were both nice and snappy there. The Peaks, I found, turned more reliably where the Sultan's turns were very snappy and sometimes a bit too quick. It is likely that is simply due to my style.
All in all, I agree with 219 and Dawgcatching, both great all mountain skis with the Sultan's leaning towards harder snow and the Peaks leaning towards softer snow.
As a note, I have a pair of brand new Peak 82s for sale
(172cm), at the moment, if you decide you are interested.