I recently decided to go to just one one-hander. Out of D4, E4, Mini Manix, UKPK and Para Mil I decided to go with the Para Mil. Thick blade, but thin flat ground. 2 oz lighter than the Manix and it doesnt' pull my sweats down like the Manix. No vertical play compression lock (my lockback spydies have a little and it bugs me). Sturdier than the D4. A little uncomfortable inside the waistband but I think that a little work on the handle will fix that.
Adam