high end subwoofer...which one tho?

hi there i'm looking for a used high end sub for home theater use not 2 channel.
i've been looking at the velodyne dd series and jl fathom,
rel, svs possibly (also feel free to make some suggestions)

does anyone know which of these high end subs are the best.
my room is 14x12 with an 8 ceiling.
i also have bass traps everywhere, if that helps.
thanks everyone