Avantgarde Uno/Duo

I think you'll get a variety of answers, depending on what vintage the Avantgardes are, and what associated equipment is being used with them.
I can speak to my experience with a set of Duos that I bought new, circa 2006 (and as to which I never did the 'Omega upgrade'). The (dis)continuity between the mid-horn (which has no X-over and hooks up directly to the amp with jumpers from the mid to tweeter horn and powered woofs) and the dynamic woofer system seems to be due to several things: the differing nature of the drivers; the inability to place the woofer in the room in a way which optimizes bass, separately from aiming the horns, unless you tear apart the speaker or run a separate woofer system; the balancing act of trying to get the gain and woofer X-over point to be as seamless as possible but still getting decent bass. In my experience the balancing act here is tricky, and rests on a knife-edge: get the output and X-over point to match pretty evenly and the speaker seems bass shy; get the woofers to kick with a satisfying 'thwack' on kick drum and they are clearly different sounding, and discontinuous from, the mid-horn.
What's surprising (or not) is that as I have improved the associated equipment, the issue is less pronounced. It is not an easy speaker to get right. When you do, it is very satisfying on a number of levels- great 'jump,' uncanny openess mids and a 'thereness' that makes listening to a wide variety of material a 'you are there' experience, rather than being telescoped inside the studio or venue. Whether the newer incarnation of the Duo is easier or more forgiving (or just a better speaker), I have no idea.
I'm pretty sold on horns though, after years of electrostatic listening. Part of the magic is being able to use SET amps.
Oh, and if you have inter-component grounding issues, or AC anomalies, you are going to have your work cut out for you with a speaker that is ~ 104 db efficient. To me, they are well worth the trouble.

PS: not time-aligned. In fact you wind up fooling with the polarity of the tweeter horns and woofer horns relative to the mid, at least on the pre-Omega version (which rectified this, at least for the tweeters). I know some folks have experimented with repositioning the tweeter horns, but I don't want to frankenstein my pair.

Whart, thanks for sharing the experience. I wonder if the right approach would be position for best driver integration, then find the best electronic to achieve best bass performance. I have noticed that Avantgarde recommends using solid state amplifiers for their horns. Perhaps, they think SS amplifiers give better performance in the bass.

I don't understand why some speaker manufactures don't pay much attention to the effects of driver time alignment.

Since the bass units are self-powered, the main amp doesn't have to be solid state. In fact, although there are a few different owners here who have used them with solid state, I've gotten pretty remarkable results with the Lamm SET. And, because one of the advantages of this design is extremely high efficiency, it's a perfect opportunity to use such a low powered amp.
If you get a chance to hear the latest versions at a dealer (I think Rhapsody in NYC may be your only option in the NE, not sure), post your impressions. I don't know if he is wedded to Avantgarde's amps, but you should get a chance to hear them with a good SET rig as well.
Good hunting!

Agree with Whart's observations. I have used Jim Smith's Get Better Sound's recommendations for speaker positioning and that helped a lot. These speakers require considerable up front care and feeding to get them sounding their best but feel like it is worth the effort- even fanatical measurements down to an eighth of an inch. Maybe I am just used to them but do not hear discontinuity that some have reported. IMO their strengths outweigh any downsides. I will say that when I went from the Duos to the Duo Omegas there was a significant improvement in overall presentation, including top to bottom integration. In fact I would say that it was probably the largest improvement of any upgrade I have made. I haven't heard the newer models so can't comment there. They do well with tubes and my system has tubes in the pre, amps and phono pre. I would guess that a large percentage of AV owners use tubes.
At one point I looked into some of the new technology like DEQX for improving both speaker and room acoustics but became quickly overwhelmed by the challenge. That may be the future though.
Good luck with your search.