I finally got a chance to A/B my two "somewhat unusual" cabinets - a BFM Omni10 "widebody" and an LDS 15/6/1 (it's built to nEarful specs, but so as to avoid upsetting the purists I won't call it a fEarful).
I know that the BFM Omni 15 would be a closer comparison to the nEarful 15/6/1, but that's not what I have, and as a player (rather than a benchmarking entity) I'm interested in comparing the horses I've got, rather than the potentially best matched horses

The Omni10 is the predecessor to the Jack 210, and mine is built at the 23" wide spec for additional bass. It's loaded with Deltalite 2510's, the recommended speaker for this enclosure, and has 4 piezos with a 3 way switch to select 0/2/4 piezos. I almost always leave the piezos on. I've gigged this cab in a lot of contexts, love the sound but found myself thinking that I might be missing out on some "bodyshaking" low end on my funk gigs. So I got the nEarful.
The LDS 15/6/1 is built to nEarful specs - 3015FL 15", 6ND410 midrange, and a horn, with the taller layout and shelf ports of the fEarful design. It is, I think, about as close as LDS gets to a fEarful and is a great sounding cab. Having only had it for a few weeks, it's only seen one gig and one rehearsal, and performed well in both contexts.
Physical Comparison
The LDS is taller and thinner than the Omni, giving it a smaller footprint and a more graceful appearance. The Omni is a hair lighter.
The LDS measures 30"x20"x16" and weighs 55 lbs.
The Omni10 measures 26"x23"x16" and weighs 50 lbs.
Photo of both cabs (yeah, I'm not much of a photographer either) <edit - at the link - pic is too big for the BFM forum>
But you can see that the Omni is wider and squatter.
Image at http://www.doumbek.com/personal/two_cabs.jpg
Sound Comparison
I used a Genz Benz Shuttle 6.0 to compare these cabs, with a Zon Sonus Special and an Ibanez ATK, recorded with a Zoom H2.
These are my subjective impressions - I don't have the tools to do a complex dynamic set of measurements.
The Omni is significantly louder than the LDS at the same settings - not surprising given that it is a 4 ohm cab (and the LDS is 8 ohms) and that it is horn loaded. I need to turn the amp's master volume up 2 clicks to roughly match the Omni's volume with the LDS, and each "click" on the GB Master is a significant chunk of oomph.
The Omni has a very strong midrange character, which I like a lot. The piezos are very transparent on the top end. Those who fear piezos for "harshness" would be very pleasantly surprised. The overall sound seems very natural to me - perhaps because I've used it for so long.
The 15/6/1 has more bottom to it. It more easily gives those "feel them in your gut" lows. The midrange character is very present, but very different than the Omni, more "noticeable" and less "natural" to my ear. The LDS has an L-pad for the midrange, and I imagine that spending more time with it I can get it to sound more natural. For these recordings the L-pad was set about 2/3 of the way up. I can see myself trying it higher.
With the lows really boosted the Omni can approach the low end of the 15/6/1, but it still has a qualitatively different feel. Down low, the 15/6/1 "moves" more, sonically. I'm not sure what that means, but I "feel" the lows more from the 15/6/1.
Samples below. One day I'll have the patience to make sure that I record "good" samples, but that day is not today, so please forgive the suckage in the playing.
Samples
Fingerstyle funk - Omni10
http://www.doumbek.com/personal/omni_fingerfunk.mp3
Fingerstyle funk - LDS 15/6/1
http://www.doumbek.com/personal/lds_fingerfunk.mp3
Fingerstyle funk - Omni with bass boosted
http://www.doumbek.com/personal/omni_fi ... k_deep.mp3
Slap - Omni10
http://www.doumbek.com/personal/omni_slap.mp3
Slap - LDS 15/6/1
http://www.doumbek.com/personal/lds_slap.mp3
The different character of the mids really comes through when playing melodically. Here is a bit of Jeff Titus' "The Glass" - a melody I'm currently working on.
Omni:
http://www.doumbek.com/personal/omni_glass.mp3
LDS:
http://www.doumbek.com/personal/lds_glass.mp3
Postscript:
I like the tonal qualities of the O10 better, except in the low end. It really is a great cab, and if I wasn't playing dance music with no PA support, it would be a done deal.
I have a feeling that I'd love an O10 or O10.5/Titan combination, but the titan is just plain bigger than I want to haul.
I might consider a smaller sub with the O10.5 as an eventual solution. I had really wanted a one cabinet solution, and the LDS does pretty well on that front, and perhaps with some tweaking it will really come together tonally as much as the O10.
Alternately, if any of you have suggestions for a smaller sub (maybe even the fEarful sub?) that would pair well passively with an O10 or )10.5, I'd be interested in hearing them.