We bought a set that we used in April last year. Just a few hints from what we experienced.
We were there at a peak time, and alot of people were using them. We discovered that even if you have the private codes, if someone else is close enough (within 20 feet), they can "bleed through" your transmission if they are on the same primary channel. Don't be surprised if you experience this, it doesn't mean your radios aren't working right. Let's face it, there are $35 family radios, and then there are $1500 professional radios.
We found the headsets useless. But, it was crowded. Alot of background noise that the microphones would pick up. You may have better luck when you are there if you try the headphones.
We used Cobras and found a nuisance with our models. The power button was on the face, right above the LED readout. We stored the radios in our packs and they would be constantly turned on or off, being bumped around by normal activities.
We tested them around the neighborhood we live in, and found the range pretty good. It was greatly reduced at WDW, probably due to buildings, RFI, other radios, etc.
We had codes for each family member. For instance, I was "Delta 1" - for Dad, my wife was "Echo 1", and... you get the idea. And yes, we had preset names for certain channels and privacy codes. We are not normally so "code" oriented, but several friends had told us about experiences with young people using insults and profanity, using peoples names. We only experienced something similar like that once at WDW.
This year we are taking just cell phones. Our coverage includes several states including Florida with no roaming fees, and we are hoping this will work just as well, if not better. Good luck, hope everyone's tips help, and enjoy the WDW experience.
