Well...I will paraphrase MBA:

As long as you have the steam, it will climb just fine. It's heavier than an XC sled...that's a given. I've been able to climb steeper/more technical sections with the XLT than I ever could with my Fisher hardtail. (I think it had more to do with the 2.35" tires vs. 2.1's than the frame) The suspension is nice on rough climbs as with any good suspension design. The rear tire stays planted well.

The "MacStrut SwingLink" design is very efficient, and if you build it with a rear shock with some sort of platform settings...you should be good to go. (manitou swinger, fox rp / dhx, Marz Rocco)

Switching from a hard tail to a dually or even an XC (short travel) dually to a long legged one just takes some getting used to. I rode with a buddy last week that had been riding a Cannondale hardtail with 60mm headshock for yeeeeeaaaars. He just got himself a AM new dually. I followed him, watching his lines. He was dodging roots and rocks, standing on climbs, and just doing what came natural to him from riding a hardtail for so many years. As soon as he gets used to the rear suspension sucking up the trail, he will begin to change his lines. I take cruddy lines on purpose just to make people laugh. I sit down through as much "rough stuff" as I can to save leg strength.

Riding the XLT to me is sorta like Richard Cunningham's description of the SantaCruz Nomad (on a smaller scale). Stay seated and pick a good spinning gear on the climbs. Any dual suspension bike will become somewhat active when you stand up and honk on the pedals, but I still do that with my XLT now and then.

I think it climbs well for its intended purpose. It's a heavier bike that loves rocks/roots/downhill sections and can still get you back to the top for more.