Do you mean for convenience, performance, ease of installation?
Bluetooth seems to do pretty good as far as connectivity goes; if this has a decently performing Bluetooth interface you should be able to mount it anywhere on the bike.
Both these devices can be charged while using them, they come with a charger that plugs into a cigarette lighter, be careful with these chargers they can't be used to charge a normal USB device (a label attached to the cord warns about this). You can also charge them with a normal USB charger with the micro USB connector.