I have used a 302, without the 303, but with Glide Nav for several
years:

1.Reliability. 2 cases of internal seal failure otherwise no problems
2. Wind calculation - not done in 302
3. Good TE compensation no problem with over-read on thermal entry. I
use 1.7 audio and 2.3 vario and see good correlation with B40 readings.
4. Reads lower sink than B40 in cruise but never ran the numbers to see
if difference matched polar. No problem finding thermals in cruise.
Not an issue.

I did replace the display as I had one with incorrect polarization.
Not a reliability issue but a poor parts screening process.

Andy