RE: Question about PCM and FM
PCM is a nice feature if you're trying to protect an expensive plane. I don't know the exact fundamentals of PCM vs. FM, but I do know that first was AM, then FM, and now PCM. PCM receivers are supposed to be very fast in receiving the signal from the tx, and you can program "Fail Safe" to help you get home if you ever lose one of your plane's functions or if there's interference.
If you're just plugging it into a a little .40 or .60 size plane, I wouldn't really worry about it. Now, if you've got a $1000 invested in a plane, then I'd probably do it. I hope this helps you.
Clinton