S3 user here, so I'll add my opinion. I ski primarily in Colorado, and used Mantras for all of the 09-10 season. Last year, I demo'd some S3's and fell in love with their playfulness- something I really was missing on the old Mantras.
I'm around 170, fairly aggressive, and like to ski all over the mountain, and I have to say, my one complaint is that the S3 seems to be easily overpowered. By that I mean they seem to have a definite speed limit. When I'm noodling through trees, I couldn't ask for a better ski, but when I open it up on tracked-out snow, they get a little chatter-y. To the OP, at 190 pounds, I would worry about the same thing happening to you.
At this point, I'm looking for a replacement ski. Perhaps I'll find myself longing for the nimbleness of the S3, but I just need a little more beef underfoot.
A couple of skis that caught my eye are the Blizzard Cochise and the Armada JJ. Between the two, I'm thinking the Cochise is more what I'm looking for, but I'm going to try and demo both. I'm certainly open to other suggestions, though!