[aprssig] which GPS to buy

[John]

I haven't been paying attention to the Tom Tom and Nuvi devices that 
have been discussed here in the past.
Now I'm thinking of getting one, so the question is which of these units 
works with APRS and interfaces with a TNC and/or TT3 type units. Do they 
output NMEA strings or a proprietary string?
Is there a site that shows compatibility?

Thanks,

John, K4AG