I'm planning to update my tranmitter from a single stick to a mode 2. A friend suggested to get the Optic 6. It is true that this transmitter will work with any receiver brand?

I have one and have run hitec, futaba, airtronics and JR no problems yet have had it for about 2 month's

I got the optic 6 when it first came out. Good radio except watch out for the flap lever on the right side. If you use dual aileron servos on CH1 and CH6 you can inadvertently hit the lever and lower the flaperons which will have dire consequenses. Make sure the flaperons are set to zero when programing and then the lever has no effect. This happened to me with a 90 size ultimate and caused a crash on its maiden flight.