Being a Pam lover, my biggest disappointment would have to be the WM white SD. Hands down the fastest watch I have ever flipped. As soon as I opened the package I knew it wasn't for me. Quality seemed good, but it was tiny on my wrist, and still needed a few modifications. The watch was on the post office on its way to the new owner about two hours after I got delivery of it.
On the other side of the spectrum, the watch that I keep going to is my lightly modded 063. I have gotten it to the point where I am satisfied with, and I just love that watch.