I haven't noticed that the Beretta values were in decline. But I'll have to say that I haven't been shopping prices on used 92/96's either, so I may be completely overlooking that fact. I did notice that the PX4 asking prices have gone up by 15% or more in the last few months. I ordered mine in early November... the same place is asking $70 more today. I've seen quite a few examples of that.
One other observation... I think someone made this point on the other Beretta forum earlier this week... Beretta doesn't put the oomph in advertising like Springfield does. I've seen ALOT of XD fans with the "gotta have" attitude with the new XD-45 ACP. Of course, I'm not talking about a few folks... Springfield has created tremendous interest and momentum with their newest offering. I don't know that you could say that with any of the Beretta handguns right now.