First of all, the specs.
According to Altra's website, for a size 9 the weight is 11.3 ounces, with a 15mm stack height, and zero drop from heel to toe. Apparently the next 2.0, which is due out later this year is a couple of ounces lighter, but a couple of mm thicker, and is supposed to have a slightly more aggressive tread.
These shoes are very comfortable. The first impression I got when I put them on is that they feel like a skate shoe. There's a lot of padding around the collar, and they're cut quite low, so around the side and back of your ankle they are very cushy feeling. As to be expected with any Altra shoe, they are very roomy in the toe box, which is one the reasons I like Altra shoes so much. The liner is quite smooth and comfortable as well- I've worn these out on trails with no socks and I had no problem with rubbing at all. There's a removeable rockplate in this shoe- I've left it in. With only 15mm underfoot, that's not much protection if you step on a sharp stop. The plate is quite flexible, so leaving it in doesn't really affect the performance of the shoe.
If you're a runner that encounters both pavement and dirt on the same run, and you want something that digs in a bit more on the trails that a standard road shoe, then these would be a good option.
Or, if you have mutliple pairs of trail shoes and you like to match different shoes to different conditions, these would be a great option for selecting when you're going to be on a trail where you want to go fast on packed/ hard terrain, but don't need a ton of grip on loose or wet terrain.
All in all, I'm quite happy with these shoes, and I look forward to trying out the 2.0s when they are released.