The FrSky Taranis system is among the very best on the planet.
It is a frequency hopping system that has a proven track record to be VERY reliable, even at extended ranges.
Why telemetry? We recommend the telemetry for the very simple reason that the radio can warn you if you are having a reception issue on the aircraft. We consider this VERY IMPORTANT. This is good for you, and it is great for the hobby. If your current radio does not have this RSSI feature, then you should seriously consider upgrading today.
Why guess if you are having any issues? With telemetry your transmitter will alert you if the radio link starts to weaken. This can happen due to poor aircraft layout, radio damage, or some issue at the field. It has saved MANY planes, and will continue to do so. No more waiting for our planes to crash!