10" subwoofer around $500, used or new?


I'm looking at a 10" sub for a 20'x11' room (in an apartment, hardwood floors).
Mostly for music (and 5% for movies). 

How much has technology improved?

Should I got for a used $500 sub which were original $1,000+ ? Eg: 
- Rel strata
- Boston PV1000
- Totem Dreamcatcher
- MJ Accoustics 100 Mk II
    ** OR **
Today's subs around $500 new will give a better sound? 
- SVS PB1000 10"
- Martin Logan Dynamo 
- Klipsch R10SW 10" 

Any other suggestions for new, or used sleepers to look out for?

Thanks!
zordex
Post removed 

Hey keithtexas, thanks for the heads up, just ordered a pair on amazon. 

george

Check out Speedwoofer.. They have an excellent sub @ $399.00 shipped that is incredible. I purchased one for my Magnepan .7's and was more than impressed. I plan on purchasing a second. Their customer service is outstanding, I talked to the owner on the phone for set up advice. Don't let the low price fool you..

@jetter - you're welcome.

I'm not sure what the difference is between that one and their SB-2000, other than the SB12-NSD has a 400 watt RMS amp vs. 500 watt on the SB2000.  I think they must be clearing out the SB12-NSD to make way for new models. Regardless, 5 yr. warranty is great and they have a 45 day trial after which SVS will still pay for shipping for you to return them. Tough to beat, everything considered.

My fabulous (!) REL Q150e was bought for 200 bucks (Ebay) a few years ago and except for a missing grill cloth (easy fix) it was perfect. A great sub. Made my own Neutrik Speakon plug cable from some good wire and saved some bucks there also (love Speakon plugs by the way).