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
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My recommendation is Gallo TR 1D 595.00 new.  It is a sealed design and is much smaller than any of the box design subs. 
" Since you say it's primarily for music, I suggest you consider sealed subs. It would also help a great deal if you stated what speakers and electronics the sub will be used with "

Currently using JBL L5s and Cary Audio SLI-80. I may not stay with this setup though, so a sub that is not to picky (is that a thing?) would be a better choice.
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