I have built 2 pair of EFE's. They are the AR.com that a lot of people rave about. You can see them in my gallery:


One is the stock AR.com crossover from Madisound. I built it as a floorstander as opposed to a bookshelf.
The other is a modded crossover for the AR.com by Danny from GR Research. The Madisound crossover was updated once by Ed after having talked to Danny. I have the updated version of Ed's crossover.
The flipped configuration (woofer on top, tweeter on bottom, is a simple fix for some of the issues that the AR.com has. See Danny's findings on the response of this speaker here:
http://www.gr-research.com/edspeaker.shtmI would describe EFE AR.com as being quite colored. They lower mids seem scooped, and the overall sound is kinda laid back. The top end is tricky, and quite hot. You can play a lot with resistor values to tame it, but it's definitely off. It does extend quite low for it's volume, but I've since built a lot of speakers and feel that this one is not in the audiophile category. It's not bad but I wouldn't write home about it. The crossover that Danny did for this speaker makes it sound quite a bit smoother, and has a more accurate and flatter response. Same drivers, but 2 different speakers.
It was a fun first entry into the DIY thing, and led me to learning a whole lot about speakers, so it was well worth it to me.
Cheers