Just got back from the convention center a few minutes ago, so I'll chime in with my thoughts before I head for dinner. Suffice it to say that Cliff and I got several Atmos demos in today. In order, I listened to presentations from Yamaha, Def Tech, Onkyo, D&M, and Pioneer.
Yamaha had a 5.2.4 setup using their NS777 speakers for front and rear L/R, the NS333 center, and NSIC800 in ceiling speakers in a semi-enclosed space (ceiling, 3 walls). Unfortunately, this demo was early in the morning, with a lot of background noise (foot traffic, mfrs still putting up their booths, etc.). Between that and the demo material, it was difficult to get a feel for what Atmos could really accomplish. However, there was one scene which stuck with me, namely a projector coming to life in a movie theater. Simply put, it was exactly where you would expect to hear such a sound come from, not just directly behind you, but above you as well. A neat trick, but I wasn't exactly sold.
Demo 2 was with Def Tech, using their A60 Atmos-enabled speakers on top of front and rear pairs of BP8060 towers. Amplification & processing was provided by an Onkyo TX-NR3030, and the demo took place in a fully enclosed, somewhat insulated space. To be frank, I didn't feel the A60's accomplished any height effects at all. What "height" I did hear was mostly localizable to the side surrounds which were placed a couple feet above ear level. If time allows tomorrow (unfortunately it probably won't), I might try to squeeze in another demo.
Moving on to Onkyo's demo, this was another Def Tech / Onkyo mashup with the TX-NR3030 and a Mythos 5.1 setup plus in ceiling speakers. Of note, I did this demo during lunch time, so the floor was a bit quieter than usual. This time, there was a specific track played (a thunderstorm) to highlight the difference between 5.1 and Atmos, which switched back and forth for easy comparison. The differences are plainly night and day when you compare like that. Other dedicated demo content was pretty convincing as well (Dolby's Leaf and Unfolding Demo). Actual movie content was a little more subtle about the improvements Atmos makes (a clip from Oblivion of Tom Cruise being chased by evil robots), but I did note a few Atmos-related improvements, a stroke of lightning coming from above for example.
My experiences with D&M were pretty similar. They were running their new AV7702 pre/pro, Snell L/C/Rs as well as side and rear surrounds, and Boston Acoustics in ceiling speakers in a fully enclosed and insulated demo space. Between this and the Onkyo demo, I'm pretty well sold on Atmos being a pretty big step forward in overall capability.
My last stop of the day was with Pioneer (Cliff had to leave early for another engagement). I spoke with Andrew Jones for a while who is a gentleman and a scholar, as well as a couple of the other nice folks from Pioneer including Chris Walker. As you'd expect, the demo included all Pioneer Elite equipment including their new line of Elite speakers which are Atmos-enabled. This time, I actually doubled down on the demo experience. The first time around, I was located to the right rear of the room, so effects naturally pulled toward the right rear speaker. The second time around, I got to sit smack dab in the center of the action (and a big thanks to the guys at Pioneer for accommodating me). So did they impress me? Absolutely. The storm demo which switched between Atmos and 5.1 was played again, and clearly demonstrated that Atmos-enabled speakers can pull off a convincing height illusion. Dolby's Leaf Demo was similarly impressive, and Pioneer also showed off a bit of music with an Atmos track from Enrique Iglesias (Bailando).
So which do I think sounds better, Atmos-enabled speakers or in-ceiling speakers? Based on what I've heard thus far I'd put the edge towards in-ceiling speakers. However, I have to give credit where it's due. Atmos-enabled speakers like Pioneer's Elite line make that gap awfully thin, and IMHO they do represent a very viable alternative.