JMHO: If you are mounting your plasma up high, thus using a tilting mount, it really doesn't matter.
From memory, the differences in the "depth" of the major manufacturers tilting mounts is pretty small. Each of their "low profile" models are easily within an inch of each other. With it tilted, my plasma is 5" from the wall at the bottom and 10" at the top. I don't believe that you'd notice if it was 1" closer or 1" further away to the wall. So IMHO spending a extra $50 to gain 3/8" isn't worth it.
Now if your set up was such that you could readily see the side of the plasma I might be more sensitive to the depth, but that's not the case with my set up (above a fireplace). I also believe that mounting heigth is a factor to consider, if mine was mounted lower then the depth might become a bigger issue. Of course if it was mounted lower then I probably wouldn't have used a tilting mount either.
I must admit that when I was shopping for a mount I was very concerned about how far out the face of the plasma was going to end up. I had this fear that it would look like it was "jutting out into the room", but it looks fine to me (and more importantly, it looks fine to my lovely wife
).
Sorry for not directly answering your question, but I hope I saved you some anguish and some money.
