In reply to Jim Walton:
I've had an Ultra Quasar since 2004 and have given it tons of abuse, eventually have given it away after it fell to pieces, however the groundsheet is the one thing that has never given out, still totally watertight and no rips. I've never used a groundsheet protector or similar, and not been too careful with what I pitch it on either!
However, everything else about the tent.... I wouldn't buy another one. I've had numerous poles snap, mainly the shorter ones, both whilst pitching the tent and while it's standing. Had a few replaced under warranty from Terra Nova (who were always great about it), but then moved abroad so couldn't do the warranty thing quite as easily.
I also found the inner and outer tended to touch quite a bit in strong wind or snow, never had too many problems from this but it's a bit disconcerting.
Condensation is pretty bad, though this may be due to the fact I had snow valances on it which stopped as much air circulation? (definately recommend having snow valances by the way, more for pitching with rocks than with snow!)
I found the porches a somewhat un-useful shape, and bad weather does tend to come in through the top of the door into the inner tent.
The outer eventually decayed, but I managed to make it last a little longer myself using regular waterproof spray on the whole thing, and silicon sealent on the outside of the seams as the tape had peeled off on the inside.
Eventually it's met it's end on a 3-month patagonia trip, with 2 more broken poles, a shredded outer from the granite, and totally bust zips (I think from just being in a windy, dusty environment). Read this thread with interest as I'm not sure yet what to get next.