Picked mine up today at the LGS. Was also considering the Walther PDP 4" full-size. After handling each one at the counter, I picked the Echelon. Just felt slightly better in the hand, and felt more solid to me. That is, it didn't have the slide-to-frame rattle that most Walthers have. I know that doesn't affect accuracy, but it's always mildly annoyed me. Since there's already enough going on in life that annoys me, I figured I'd go with the gun that doesn't. Oh, and it was $10 lower in price. Hey, 10 bucks is 10 bucks!
So far,I'm impressed with it. Haven't gotten it to the range yet. Hopefully this week. But it fits my hands well, seems well-made, doesn't rattle, looks good, has a really good trigger - with an amazing reset!, low bore axis, and has excellent mag capacity. If it proves reliable and accurate, that'll complete the package.
The only weird thing with mine is that instead of small, medium, and large backstraps - it cam with 2 mediums and a large. Phone call on Monday....