Astounding
I'm a BG dealer in SW Ohio and can vouch for several products in the BG line. I recently loaded up the truck and did an in-ceiling shoot out with several different brands is some new construction homes (as well as my own home) that were near being completed. I did this not because I'm unhappy with BG or any other brand but because we're dedicated towards continuous improvement and I like to bring in different brands to compare.
I can tell you that as far as architectural products go, the BG PD-6C ($600 per pair) is, without doubt, the best in-ceiling speaker for distributed audio I have ever listened to as is their in-wall counter part. And I say that regardless of price point and without location issues. We tried these speakers in a vaulted ceiling, in a tight attic space, and in an open attic space. The BG's performace was uneffected.
We used a wide range of brands and price points varried accross the board from $150 per pair to $1500 per pair MSRP and the BG's performed the best and it wasn't even close. Brands: TruAudio, Parasound, PSB, BG, Sonance, Boston, Dayton Loud Speakers, Phase-Tech, Proficient, NuVo, RBH. The Bass out of the BG 6" trumped that of the 8" PSB, Parasound, Boston, and Sonance by a country mile. With the other brands I only had the 6 1/2" models and the BG killed those too. You have to listen to the clarity of these to belive it. We listened to Clapton, Cold Play, Garth Brooks (live album), Sheryl Crow, a classical mix, a techno mix, and just for kicks even some rap. The source was just a plain entry level Pioneer two channel receiver and Pioneer CD player.
The Bg PD-6C litterally sound like someone put a very high quality bookshelf speaker in the ceiling. Some of the other brands were OK, but for an upper-tier speaker for distributed audio I think you would be hard pressed to find better in a 6 1/2" or even 8" (depending on ceiling hieght) speaker. The BG's blended into the ceilings really well too. A lot of inceilings tend to be too white, or too almond. The Bostons looked good (but are GIGANTIC in cut out size). The PSB's and Sonance looked very good, but again, the BG's blended in with the ceiling really well. They are pleasant to look at while not standing out.
I have not used their box product at all nor have I done the $15K a pair in-wall stuff. For a theater that expensive, I would look at other options. Like Phase Tech dARTS or some of the Meridian product. I hope this helps and if you have other questions or want to give what aplication he recommended BG (and what models) for I could help you more.