The PDG is a great boot. I've used them with 163 Atomic Ultimates, Dynafit Broad Peak 167s, and 181 Voile Chargers (only on a real powder day though). Anything <80mm waisted skis, the PDG will drive well. For the price, you really can't beat this for a race/lightweight touring boot.
-The walk mode is incredible! I have the TLT 5 Mountain, and the PDG blows it away. Forward flex for skinning is really good. It is pretty resistance free both fore and aft. At least as far as my ankles can move comfortably. The Aliens are probably even better, but the PDG is pretty adequate as well.
-They are really light. I could tell a noticeable difference in the weight. Listed weight is 790 grams or about a full pound lighter than my TLT 5s. I don't have a gram scale though so I can't say what the actual weight is.
-They are pretty comfortable right out of the box. I had to do NOTHING for the PDGs to feel comfy.
-They are STIFF! I saw someone on the interwebs say they heard the PDG to be "in the same realm of stiffness as the old F1s." No way--these babies are a little stiffer than my Mountains (without tongue). That surprised me.
-I like the color.