SVS 25-31PCi vs. NHT Sub One

I am looking to buy a used sub to go along with my paradigm monitor 3's. I have a budget of $400 or less. I have come across an SVS 25-31 PCi for $400 plus shipping, and an NHT Sub One for $325 plus shipping. Does anyone have any suggestions on these 2 or any other suggestions. They are to be used 50/50 HT/Music.

Also, i have heard the SVS 20-39PCi and love it, but Im not sure how the SUb One stacks up against the 25-31 and if it would be worth the almost $100 difference. Thanks.

Of the two, I'd go with the SVS. That being said, if you can find a used VMPS sub and something to power it with that would be the route to go (best of both worlds).

Note: I have a used VMPS Large Subwoofer (closer to their New Original Subwoofer) and a SVS 20-39CSi both powered by a Samson S700.