Okay I go first.
I guess the strongest aspect of the system is its dynamic scale. Few systems can match it in how it shifts air but also how it makes sense of complex music.I guess it biggest strength is it is effortless sense of flow.
It could be a bit better lower down as cutting off about 28hz however the quality of the bass is very good. It also allows you to hear timbre (this is something it also excels in). I could always get some Daytons UM18 to go down to 20hz if I want too But to be honest I would only occasionaly need it.
My next upgrade would be some decent field coil drivers as they would give me a more immersive soundstage without sacrificing the dynamics I get. Not that my soundstage is poor.

Well.
Fwoof.
I dunno - I just like the way it sounds.


It does imaging very well. I do particularly enjoy that aspect.

Apparently my system has got impressive "height" . Several audio-buddy visitors have told me that. I haven't really got a clue what that means, though. But my system does it well, so that's good.

There's a purity and naturalness to the sound that is often very entrancing.

I try and avoid the ultimate in transparency these days, although the speakers are very capable of achieving impressive results. I find I choose a combination of electronics that puts a slight but noticeable 'cushion of air' between me and the music, I find that more closely emulates the real concert experience of sitting about two thirds of the way back in the front stalls, my preferred seat at a classical concert.
I don't really want to sit on the conductor's or soloist's lap, which is where a too-revealing system can put you with many recordings.

The good: Big scale. Pretty detailed and very dynamic and vivid. Does human voice very well. Powerful and extended bass. Imaging and depth (now, it didn't used to). Note decay and low level stuff.

The less good: Not very forgiving. Doesn't polish a turd.

My system is very tweakable. I do this by switching power amps. Class D, 300B SE, EL84 PSE mostly though I also have a 306 and EL84 SE. The Bastanis are like huge OB headphones, twin 12 inch drivers per side (plus tweeters and bass drivers). I like my music to be a wash-over-me immersive experience with more intimate music / jazz - with the valves in particular this is what I have, with Class D for more modern music I have a more impressive sound. I also have two other systems which aren’t shabby either. Currently I have Diana Krall - Live in Paris playing via 300Bs, a great combination...fluid, immersive, atmospheric.  How can I describe how it delivers emotion?  I can’t but it does on jazz in particular.  Of course I’m part on the equation too.  On Class D it’s dynamic, more analytical and instantly impressive...but less emotional but this is what Pink Floyd, Led Zep, Genesis etc need.

I’m not deaf to SE valve amp shortcomings...IMD is very present on rock and full orchestral music so that’s when I use other amps.

The bass setup is different to my profile pic...no baffle at all, more like John’s.

"improving it" without actually making it sound crap.

This should be a mantra for all audiophiles Paul! LOL ...

Well I place my speakers in the weird category. What do I mean by that? Well, it's an unconventional technology.

Jerry's MBLs get this award also. They are plainly weird.

Weird speakers sound different to your run of the mill dynamic drivers. Mine don't contain any dynamic drivers.
Positive virtues:

1) Bass driver - a planar magnetic panel, extends to 20Hz and that's +/- 0DB. No subwoofer needed and indeed trying to use one didn't work, really. Even what was a good one like a Martin Logan Descent. The articulation and definition of bass is hugely impressive and I haven't heard any dynamic drivers equal it, though they can definitely play louder. Overall the bass panel is calculated to be the equivalent of three twelve inch woofers.

2) Consistency. The entire frequency range is covered by the same materials. Foil, glue and Kapton. One reason I was attracted to them. There are few speakers that cover the whole frequency range from 20Hz up with one driver material. Consequently they sound "of a piece".

3) Speed. Reading a review a while back, the author noted that the are very few speakers capable of making decent stab at reproducing a square wave. They just aren't fast enough to do it. The blinding speed is very noticeable reproducing drums, or as AV speakers where gun shots and the like are immensely impressive.

4) Unlike most ESL hybrids, the bass panel is the same height as the mid/treble driver. Consequently the speaker sounds balanced from bottom to top. It also betters most dynamic speakers where the bass is often emitted from the bottom of the speaker too.

5) Shock factor. Truer in the smaller room I used to run them in. What I mean is the look on people's faces when they hear them at volume for the first time. It's pretty obvious they are stunned. They've never heard the like of it before! In a much larger 35 by 14 room there's definitely less of this, but they still do a pretty good job. However, at 12 foot away in a 17 by 10 room, they were overwhelming. Massive information overload. I kind of miss that aspect of the smaller room.

Negative virtues.

1) Too much information. This doesn't bode well with bad recordings. It really exposes them for what they are. Also, choice of amp and other ancillaries is critical, as you can so easily hear the differences in kit. Valve rolling exposes differences in the valves in an obvious manner. One reason I now use an expensive Luxman pre/power combination is it is the only amp set up I have tried that feeds the speakers with detail in a manner that complements them. Out of the 30 odd amps I have tried this is the only amp set up that really succeeds in getting it right. That's pretty ridiculous, really. It took a long time to get there.

2) Maintenance. All planars require maintenance to have them running tipperty top. It applies to Martin Logans and other ESLs too. Pain in the arse, TBH.

3) With some recordings there can be a feeling of an overly etched mid range. I am not sure if it is the speaker revealing the recording's limitations, or it is a facet of the ribbon mid/treble driver. I have spent hours messing with the crossover to reduce this, with a good deal of success. But I'll never get rid of it entirely.

4) Mid/treble ribbon dispersion is a little strange, very unlike most dynamic speakers. That's because the sound is being generated from two long, very narrow vertical slits. It's not that even as you move from side to side, however, it is a lot better than a Martin Logan curvelinear panel, where you literally need to sit with your head in a friggin' clamp!

Now are they speakers for everyone? No I don't think so. For some they are plainly just too much. They demand too much attention from you and place you into a state that really isn't relaxing. But on the other hand if you crave excitement and sitting there in a totally perplexed state, then they most definitely are!!