Your eGo usb charger is a 420 milliamp, 4.2 volt charger as are all eGo usb chargers.
You are looking for a usb wall charger, right?
All of these usb "wall-warts" have an output of 5 volts, and range from .5amp (500 milliamp, and the most commonly found) up to 2 amp. The only real advantage to a 2 amp wall charger would be if you have a pass-through eGo battery.
From the cheapest to the most expensive, your charging times will vary little if at all, and quality difference in reality is illusory. Your usb charger plugs into the wall charger, and that is what regulates the charging. You can pick up a usb wall charger darn near anywhere and any of them will do the job.
The length of time to charge is determined on your batteries mah capacity, whether or not it has added circuitry (such as a variable voltage twist), and overall condition of the battery.