Do these work well for volume control on an amp?

Guys, I am looking at adding 4 bullet 770's and am considering a JL Audio HD 600.4 and Alpine PDX4.150 - the one feature I do want is the volume control knob that is available on the JL Audio, apparently you cant get that with the alpine. But, I like the Alpines small footprint.

Upon investigating, it looks like you can add volume control to any amp using this thing: http://www.woofersetc.com/p6457/RLC--Scosche-Remote-Level-Control.htm

I know we have some serious stereo guys on here, can anyone tell me if this thing would work, and work well??? I dont want a "hokie" set up...

Thanks!