Andy - Well, a GPX 5000 costs over $5000 so that is not a possibility for most of us, me included and depth is just one aspect as you mentioned. LOL, but I see your point.
I am in Germany and hunt in typical European iron, so I understand that "target seperation, iron rejection, speed of recovery, weight, ease of use", etc are perhaps the most important factors. But being that many of us can't afford multiple machines or just like to learn one machine well, I'd like a unit that gives me the best chances overall - No, it won't be best in every category. So, the E-Trac has come closest thus far for me. But, due to it's weight, I'm looking (and actually have been looking at the Deus since it came out here).
So, I think it's a very fair question to ask regarding just the depth. We all know (by now) the Deus is TOPS in the quoted areas above.
Raymo - thanks for the information. It is very nice to know and the comparison helps to understand. Really looks like the Deus might work in my iron mineralized soil here.