My 09 GF Hifi Pro came with Bontrager Rythm Elites. Trek dealer warranteed my back wheel with a Rythm comp. arghh.

I am looking to upgrade my wheels before Tahoe Trail 100 this summer. Saw this on Hucknroll/Amazon: Amazon.com: Shimano XT WH-M776 All-Mountain - Wheel or Wheelset: Sports & Outdoors . Looks like a very good deal if they're better than what I have.

So here's my question....I'm trying to figure out if these would be an upgrade on what I have now or if I need to spend a grand on cobalts or something like that? Since I weight ~200lbs with gear I do need something relatively strong...so really what I'm looking for is same strength but lighter. Suggestions for any other good deals you've seen would be MUCH appreciated.

Thanks for any and all advice on this.