Does it need to be waterproof for M3W use? Consider lifetime map updates, Garmin allow one off purchased updates or a purchased lifetime updates for those that are nor free. Does it need Bluetooth for an earpiece as you will not hear the built in speaker above 30 mph? Do you want traffic info, FM traffic is non subscription but not as good as one using a data connection.
Have a look at
http://www.pocketgpsworld.com/where you will find reviews but unfortunately you cannot tell what's recent so check if one you are interested in is there. You can get a subscription for points of interest (speed camera).
