The FAA has a contract with WSI to provide the weather data, so there's no subscription cost to the A/C owner.

Really?! How come WSI charges $599 for the weather subscription?
http://www.wsi.com/solutions/aviatio...ht/pricing.asp

I have the MX20 with WSI (and Jeppesen approach charts) in my airplane
and I am very satisfied with both.

Gerd