Some History of Radio Controls
Don't bother buying or trying to use an older, 1991 or older radio system to control your aircraft — it's just too risky and dangerous for others flying with you. If you've an old one that is pre-1991 but was created after 1988, you might be able to upgrade it, but it's still best to just get a better radio. They're more reliable and have more features.
Even some servos that are 20 years old can still work with most modern systems. But newer servos are CONSIDERABLY lighter, faster, consume less power, and usually have twice or more torque compared to any servo from the 1970's or 80's.
I have personally used mostly Futaba radios over the years and found them trouble-free. I have also tried FrSky & Spektrum which are quality brands for their transmitter options. For servos I've tried just about every brand there is. I still think that Futaba is a great brand for general r/c flying. Recently there are these considerably more expensive servos from MKS and KST that are amazing.
Years ago, I used brands like EK Logitrol and Kraft, neither of which are still in business (and they were rather unreliable!).
Most servos from different manufacturers work with most major brand systems — the key difference is the connectors and wiring. Most of my planes have a mix of different branded servos and receivers, but be careful — if you incorrectly reverse the polarity, a servo's electronics can be damaged permanently.
See also: Radio Systems · U.S. Frequencies · Servo Wiring