The DX3R is not compatible with telemetry out of the box. To use Telemetry with the DX3R you'll need an SR3300T or an SR3001 or SR3000 and the telemetry modules and handheld unit. The DX3R will not display the telemetry information on the main screen, that's why you'll need the handheld unit. If telemetry is really the thing you're looking to do then I would get the DX3S.

The DX3R is faster and more responsive than the DX3S. The DX3R uses DSM2 technology as well which gives you the faster speed and features such as ModelMatch. If you're using digital servos and speed and responsiveness is the most important factor then I would go with the DX3R