Hmm. Is that "new" or new from an Aqualung-authorized dealer?
If you buy the new reg from an authorized dealer, you'll get the manufacturer's warranty which includes free-overhaul-parts-for-life so long as you service it at the manufacturer-specified intervals. The value of these parts is about $50 whenever you decide to overhaul the reg.
If you buy a secondhand "new" reg, you don't get any of these benefits.
Before you jump on this deal, I would research how much a new Titan LX costs through an authorized dealer. New with the warranty the MSRP is $440, but I think you could do significantly better if you try to cut a deal with a local shop.
The Titan LX is a great, workhorse reg. Titan regs are used by a lot of rental operations. The inner parts of the second stage are identical to that of the Aqualung Legend, but the first stage is definitely different.