Its not actual lag so much as poor UI choices that are perceived as lag at this point in my opinion, but I most certainly can 'feel' the lag.
We're currently finishing up a fairly simple music app for Android with a couple of fun features.
In the beginning we were fussing around a lot with the Android UI and Audio APIs, as the lag when a user pressed a button widget until audio was played was very noticeable, we couldn't get rid of it. After hitting a brick wall we simply started from scratch using only a blank canvas, manually drawing buttons and handling events and the like and things worked perfectly.
So I the lag we (and probably everyone else) experiences has little to do with Dalvik but everything to do with the Android UI widget event handling, it causes unresponsive UIs.
I never noticed it before but now I see it all over the place. The only apps that don't have it are games and apps like ours who sidestep most of the Android Widget/Event API and go the manual route.