...I've read elsewhere that the wifi only model has a harder time interpreting the incoming data from external GPS devices and is prone to problems vs. the cellular model, is this true?
I can't comment on the above, but I can tell you that the cellular model has an internal GPS, obviating the need for an external GPS, but is more expensive than the WiFi model, which does not have an internal GPS and therefore requires an external GPS unit.
A friend of mine got caught out by this. He purchased the WiFi model because it was cheaper and then discovered afterwards that he would have to shell out for an external GPS -- an additional bit of kit to lose/go wrong/keep charged etc.
If you choose to purchase the cellular model, you are not obliged to sign up to a data plan or insert a SIM card in order for the internal GPS to work. However, a data plan would give you the advantage of being able to update weather and notams etc when out of reach of a WiFi signal. Hope this helps.
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