RE: Is there a radio that does not lose signal?
Futaba and Spectrum are the most common brands. You can start a long debate, either one seems to be reliable.
Spectrum's brown outs were mostly caused by weak batteries or too much load causing a voltage drop, Spectrum reacted with shortening the reboot time for the rx and recommended a 6 Volts rx battery.
Some die hard users swear by 72 Mhz, I had bad experiences with that and no problems at all with my Futaba 8FG.
I would not go back to 72 Mhz. For FPVs, range can be an issue and the old radios seem to reach further, under normal use you will not get your plane out of range with 2.4 Ghz.
If you fly electrics, Spectrum's telemetry functions come in handy, Futaba has those only on their high end systems.
What I'd do is set a budget, then compare what the manufacturers offer for the money.
Also the price of the receivers should be considered.
I use mostly Futaba 617s, they are around $70 if you look around in the internet.
For the cheaper planes I use Frsky, Orange and Corona, they are $25 - 30 and I have had no problems with those.