Well as luck would have it, I got the chance to finally hear a set of line arrays. I've been as curious as everyone else as to what these things sound like compared to the more common configurations. They were not Danny's LS 6's however, but were McIntosh XRT2K's.
These are 7' tall and feature 6 12"aluminum woofers, 64 2" inverted titanium dome midrange drivers, 40 3/4" titanium dome tweeters. They are sealed box design. Anechoic frequency response, 16Hz to 45Khz. They are 80k for the pair.
I had a really good critical listening session with some material that I'm familiar with, so that was helpful to really focus on the characteristics of these line arrays.
Danny's description as to the things to expect are as good a description as I think one could give without writing a book.
It was really neat to finally hear a line array. You might think that the listening chair should be equipped with seat belts when you sit in front of 7' tall speakers being driven by 2000 watts of amplification. But it's not a sonic assault at all, although I'm sure they could be obscenely loud.
At normal listening levels, if you had your eyes closed, you would never guess that they were 7' tall. They do disappear into the room.
Just for the record, I was not left dissapointed when I came back to listen to the OB 5's. My next pair will probably be the OB 7's. I think the additional 2 woofers in a sealed box coupled with active 12' woofers is going to be as close to a line array as I'm ever going to want. The mid range of the OB 5/7's are really unique, and the highs of the Neo3 are stellar.
I'm glad I got to hear the line arrays, as the question was nagging at me a bit. While arrays may have more of certain elements, the OB 5's are not really lacking at all. I think even more of them now. They are real overachievers, and a real bargoon to boot. If the arrays are 9 out of 10, then the OB's are easily 9/10 of the arrays.
I'm that pleased with this speaker. And can hardly wait to upgrade my front end feeding them.

Cheers