There is a general consensus in the silencer market that only the latest and greatest are worth looking at/talking about/buying.
The fact is, there are cans designed and built a few years back that are still good cans. I paid $150 for my TAC-9. Sure it has the old fashioned threaded locking collar instead of the spring loaded kind that is seen on all the new 3-lug cans. Sure it weighs a lot, it's made of stainless not titanium. The other thing about it, it's quieter than a new Raptor II.
Theo talks about marking old cans down to get rid of them. I feel like I missed out on a deal. There are plenty of old suppressors I would be happy to own. (The SPR/M4 especially)