In reply to stevev:
We've got half a dozen pairs of each for clients to use. Firstly, whichever you chose, get the ascent version - it has a heel raise for steeper terrain. The bindings are more or less identical.
The Evo is heavier but is much more sturdy and a bit more durable. It traverses on hard snow better. It has an extension that can be fitted on the back to give more flotation in deep snow, though neither of us have ever bothered using it.
The Lightning is, well, lighter. It is nicer to use in deep snow than on hard stuff. It is more flexible than the Evo. It doesn't traverse as well. It is a bit flimsier. The flexible deck can get frayed and cut where the boot comes down on it, or by a particularly abrasive crust on the snow.
Overall, I prefer the Evo. Just a personal choice really, but based on the above. If you are heavy, I'd go for the Evo. Both have more or less identical bindings. We've seen a few breakages, but given the use thay get I'd say probably no more than other makes.