Peek the Geek

Has anyone had experience with Excel Sports' custom build wheels?

I've got a $250 gift certificate to Excel Sports, and I thought I'd put it toward a new wheelset for my 2004 Marin Pine Mountain. I don't need a high-zoot wheelset, but I would like something that will be an upgrade from my Marin's stock wheelset (WTB Speeddisc rims and WTB Laserdisc hubs, if I recall correctly). $400-500 for the wheelset is about the price range I'm shooting for.

There aren't a whole lot of options through Excel, but I was thinking of going with DT Swiss 370 disc hubs, DT Swiss XR 4.2d rims, and 14/15 double butted spokes.

I'm not overly concerned about strength, as most of my riding consists of cross country singletrack, no drops or jumps, a few citizen class races per year (strictly for fun). And I weigh 165 lbs.

So, my questions would be:

1. Does the spec sound like it would be a noticeable upgrade from my current wheelset? Is it worth the money spent?
2. Could I get more for the money elsewhere, picking up a different wheelset Excel doesn't offer (they tend to be pricier on most stuff and have limited options)
3. Would I be better off with XT hubs and Mavic 717 rims?

Thanks