Soundman- I was faced with the exact same decision as you. I sold my Def Tech Supercube Reference and bought a pair of cherry MFW-15's for two different theater systems in my home. I did a ton of research and lost a lot of sleep. I was very hesitant to purchase a sub that I had not heard, and would have to wait 3 weeks to receive, but now that it's all said and done, I believe I made the right decision.
I'm sure you would be happy with either one, but the value of the MFW's is almost too good to be true. I'm a very impatient person by nature, so this was an extremely tough call for me. For some reason, it seems like all the subs in this price category that are worth buying are on big-time backorders. That's frustrating to say the least. Good luck with the decision making process and I'll provide an update around the 9th of May. (If I'm lucky, and they ship when they say they will.) On a side note, I found the customer service at AV123 to be excellent.