There are lots of tests of these types of products on the interwebs. Best results probably depend on many factors. Here is another one where my choice (LPS 3) is the clear winner.
Protective spray??? - Page 2
Anyway, if it bothers anyone to spray the inside of your frame, don't do it. I don't really see a downside. It takes like one minute. Exposed steel rusts; that's what it does. Will it rust through enough to fail during any reasonable service life? Probably not. Doesn't hurt to give it a little more TLC though, especially thin walled racing frames. For me it just seems natural. I have a lot of steel hand tools, and wouldn't dream of letting them sit around without a light coat of wax or oil.