RE: Which radio to get...hmmmm
Model Match and Servo Sync are features of JR/Spektrum 2.4 radios, but not Spektrum 2.4 RF Modules.
When you link a 2.4 Tx to a 2.4 Rx it is called Binding. The Tx sends out a Unique Signature to the Rx and once the Binding process is complete, the Rx will only accept signals from the Tx it is Bound to. The Rx remembers that Tx signature.
With Model Match, not only does the Rx remember the Tx, but it also remembers which Model Memory the Tx was set to during the Binding process. This means that if you accidentally set your Tx to the wrong Model Memory for your aircraft, the Rx will not recognize the signal until the correct Model Memory is selected.
If you are using a 2.4 radio that does not have Model Match, even though the Tx is Bound to the Rx, if you select the wrong Model Memory, by accident, the Tx will still communicate with the Rx and you could lose the aircraft. It is a nice feature, but we have been using radios without Model Match for years, both 2.4 and Non-2.4, so it is just an additional safety feature.
On one of these RCU threads, someone advised me that the Airtronics SDG10 has a similar feature to Model Match only they have their own name for it.
When you are mixing channels, in a Tx, using a Programmable Mixer or a Canned Program such as Elevons, Flapperons, etc., the two Mixed channels may not be close to one another (for instance Ch3 is mixed with Ch8). When the Tx sends a signal to Ch3 and Ch8, Ch3 receives the signal first and Ch8 receives the signal second. Sometimes, there is a noticeable Delay between when the signal reaches Ch3 and when it reaches Ch8. If this were a Dual Elevator mix, you might see one Elevator half move before the other Elevator half.
Servo Sync re-prioritizes the Channel Order, for mixed channels. With Servo Sync, Ch2 and Ch8 get the signal at the same time.
Model Match is for Safety and Servo Sync is for better control.