Doug wrote:

Probably the least understood feature of an IFR GPS is OBS mode.

I don't know. The knowledge level for a lot of folks is pretty meager on
functions other than the OBS mode.

The training leaves a lot to be desired.

I took a good friend who was getting no where with his Garmin 500. We spent
two four hour sessions using the trainer at a PC, and now he is a pro.