I have the 4443A1, Liner Lock G10 version, and its a little sluggish flipping. I think it's a blade weight issue like GCG199 pointed out above.
I've never really carried mine all that much and the pivot seems a little stiff, but I usually have to give a little wrist flick to get it to open. Judging from the tightness of the pivot, it might loosen up in time. At the time I bought the knife, I picked it up for around $70, so a sluggish flip seemed acceptable. The Ti version costs a lot more though.