I also vastly prefer 34xx over 37xx. However the succinct advice by aekhong '
Just try it' is correct. There are whole threads in Noeman and elsewhere devoted to problems experienced by some users due to satellite accuracy problems after conversion. In some cases minor and dismissible, as found by both myself and Kanopus with our converts, but there are many more reports of accuracy loss severe enough to be concerning. Perhaps that's because the ones not having such problems aren't reporting it, and the others are. Read this thread:
[Only registered and activated users can see links. Click Here To Register...] and then decide for yourself. It's now very easy for novices to convert and reconvert using the sd method. Heed the advice about NV backup and you won't risk anything. If unhappy you can always come back to 3790. Apart from the 34xx features already mentioned, such as Guidance 3 navigation, there's Android Smartphone link, and you can enable extras such as Video & mp3 players, so you may wish to read this thread also:
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