Another happy TLS-350 owner here. I use mine to penetrate deep, dark, ragged NJ wrecks (the "real" kind of wrecks, not the sanitized kind you find carefully placed next to a reef in some "pretty fishy" resort location) and have NEVER had any problem with the material's durability. I'll let others who don't actually dive one conjecture, guess, or suppose that the material "seems too light" or "feels less durable" than other suits. I can only speak from my experience of actually owning one and having done 300 or so wreck penetration dives in it.
On top of that I'll add the experience of every other TLS-350 owner I know and dive with in the same environment, including those with 1,000's of dives on their suits. Sure, some of the folks who really get down and dirty digging for artifacts, wielding hack saws and crow-bars, etc will opt for a CLX-450 or an FLX50-50, but even some of those guys/gals are found in TLS-350's.
The fact is the finish of the material is quite smooth/slick, such that if it does come in contact with some ragged edge it sort of glides right over it. I had a top-end BARE trilam suit originally, and while it "seemed" more sturdy than the DUI, the rougher material tended to snag on stuff that doesn't bother my DUI at all.
Are they a touch more expensive than other suits? Yup. Do they actually cost the prices that detractors like to quote? Not usually. People love to compare a custom cut DUI with all the options to a non-custom suit from another manufacture's standard line. If you happen to fit into in a standard size DUI suit (and most folks who are within two-standard deviations of a "normal" size will) you'll be able get a TLS-350 with the most popular options for under $2k...
DUI TLS-350 Suit for $1,650 at www.DiveSeekers.com
Give Wayne or Jason at DiveSeekers.com a call and see what they can do for you. Note they also sell BARE and Whites, so they can hook you up whichever way you want to go. Rest assured, they will NOT try to sell you a DUI if it's not the right suit for you!