Sub for $500 - Adire Rava or Hsu VTF-2? Others?

I currently have an NAD C370 with Axiom m22ti's. Am looking to get a sub that will be strictly for music. Have read lots of stuff on the Adire and Hsu. Can anyone out there make this process a little bit easier? Will I notice any difference between these?

Thanks in advance.
I really liked the flexibility of music vs HT with the VTF-2. One of the best for the money in my opinion.....

I would actually try to find an Now Discontinued B&W ASW500,
which I auditioned for a lengthy period of time a few years ago. Next to REL's for music this little 70w Mosfet 10" front firing sub was amazing! The internal amp was made by Rotel for this sub, & was rated down to 32khz on paper. New price was $500 Used today seen anywhere from $190-400.
I second the Hsu VTF-2. There are better subs, but not at it's price. Does a great job at music and HT.