Columbia Sportswear took over Montrail in 2006 (I think) and discontinued the Hardrock a couple of years ago. They told me that the new AT model would be the same, but it isn't--not much structure and far too wide in the heel.
The '07 Hardrock was not affected. The '08 Hardrocks work fine for me but only with added arch supports. The '09s didn't work for me at all--they generally feel like bedroom slippers. I have weird, almost crippled feet (bunions, hammertoes, fallen arches), so need lots of support in my shoes. Please note that I'm talking the women's version here.
I bought up several pair of the '07s and '08s, so I'm good at least through this year. After that, I'll be looking hard for something that will work for me. It will have to have really narrow heels, good arch support and a wide and high toe box.
Moral: if you find the perfect shoe, buy up a bunch of them; the models will change next year!