I will be buying an Acoustically Transparent screen, 2.35:1 and have narrowed my projector choices to the Panasonic 3000U and the Sony HW 10.

Is one preferable? I will be watching 50% movies (Blu Ray and SD) and 50% HDTV with this 2.35:1 screen.

No Adapter Needed

Like most projectors, Sony HW10 needs an adapter. AE3000 passes Cinemascope images directly through its lens. For the moment - and how long is this moment? - Panasonic's direct lens imaging may be the best available. You can be sure projectors with native 2.35 panels are coming.

No Adapter Needed

Like most projectors, Sony HW10 needs an adapter. AE3000 passes Cinemascope images directly through its lens. For the moment - and how long is this moment? - Panasonic's direct lens imaging may be the best available. You can be sure projectors with native 2.35 panels are coming.
Sort of kinda correct...

The "adapter" is a Lens.
Both projectors throw the same image (16:9).
The difference is the panny can remember your zoom location when you zoom to fill the 2.35:1 the screen. You would have to do it manually with the sony.

No "Lens" Needed, Not Ever

That's right. AE3000 comes with robotic lens control and you never have to get up and zoom to fill your screen and then get up to un-zoom back to 1.78. Like many other projectors, with HW10 you might buy a video processor for vertical stretch, and with that, add a heavy and clumsy "lens" that may drop and injure your guest.

You ask, "Is one preferable?" You'll be happy with either projector, but for your purposes as stated, including a Cinemascope 2.35 screen, Panasonic provides the most elegant solution for today. For tomorrow projectors with native 2.35 panels are coming.