I too have iGo8 (8.3.4.102680) running exceptionally well on my TP2...even with an 800x480 skin enabled.
There is, however, about a second or so of lag behind my actual location and the location displayed on the iGo interface. But honestly, its really nothing to complain about; and to paraphrase another member's post above: its not to the point where id be missing a turn or anything crucial at all. Im very pleased with the TP2's GPS/iGo8 performance thus far.