I am currently using the 6exas for my 4 *. This is my second plane. The 6exas is fine for my skill level, however, I am already starting to look into another radio. There are two reasons for this.
1, the plane I am currently building will have flaps and retracts. This leaves only one channel for each of the functions, which leaves no room for added functions or separate channels for ailerons.
2, I fly from a crowded field and I am considering a multi frequency radio.

The Opti 6 gives me multi frequency, but still 6 channels. The 7CAP would give me one more channel, but is fixed frequency.

The two radios I am now looking at are the Opti 7 ($218 at ServoCity), and the 8 channel Tracker III which is about to be released by Polk ($200). There are features of both that appeal to me, but I am leaning toward The Tracker. The features that are attracting me to the Polk are, the extra channel for the price, the frequency is selected electronically and does not require removing the synth module, and when you select a frequency, the radio will not start transmitting if the radio detects usage on the same channel.

Scott