For most users either 37x0 or 34x0 will suit everyday needs. Maybe just try the conversion and see how you like it as 3490, if you don't like it then convert back as it's pretty foolproof but keep in mind there's always a risk when you cross-flash firmware. Some 37x0's had different GPS chip to other 37x0 and 34x0 so they can suffer inaccuracy due to not having complete compatibility with 34x0 firmware, so you should read this too: [Only registered and activated users can see links. ].