I have been trading emails with Garmin tech support regarding the "drift" issue with the Vista HCx. The conversation has been cordial and my sense is they are genuinely interested in resolving the issue.
I had sent them a track log - not just a screen shot, but the *.gdb file that was saved in MapSource - from a hike that contained a very obvious "drift". I also included some description of the hike that corresponded with various points in the log. I also brought to their attention a couple of the threads on this board where we have discussed the issue.
"drift", as we have used the term here, apparently is not part of their vocabulary. They did mention an issue with "multipath" but, as they described the issue, that issue does not seem to account for the fact that the Vista HCx has difficulty "finding" itself again after the "drift" has occurred.
Here is the last response that I received: " We have contacted the Engineer's with your last information and they have stated that they are working on a software update that should help resolve this issue. They believe this is partly due to this unit being a high sensitive GPS receiver.
Imho, as end-users, be are, in effect, beta-testers. That is not intended to be a criticism of Garmin but the reality of being consumers of all of these interesting electronic toys. Thus, it seems to me, that, if we really want these toys to perform to our expectations, we have a responsibility to make it easy for Garmin (or the other manufacturers) to fix these issues. I would encourage others to share track logs that have an obvious "drift" with Garmin. Note, that the "drift" issue is a track log with an obvious aberrant track leg that significantly deviates from the actual route and then has the appearance of returning to normal.