While I have no experience with CorrosionX let me weigh in on two other products mentioned in this thread.
First, FP-10. I've used this for awhile and it's an outstanding lubricant, a decent cleaner, and from what I've read, works well to prevent corrosion. It's a better cleaner than BreakFree CLP, IME, but I still prefer Hoppe's for cleaning. I don't live in an especially humid area so I've never really had rust problems on my guns, no matter what I coat them with. I just ordered another bottle of FP-10 from Midway.
I got a free sample of Militec-1 oil and grease. Both are very good lubes. They are not intended as corrosion protection AFAIK, and the oil has performed poorly in such a role in one or two tests reports I've read. Interesting note, though: Benchmade Knives specifically recommends Militec-1 oil to lubricate their folding knives. It works really well in this role, since after it dries out it doesn't act like a magnet for pocket lint.
I look forward to seeing a detailed review of CorrosionX.