Late to this party but one way you can get an idea of the differences in prices between your Prestige and your frend's Rockbass Corvette is to see what they go for new. Will give you just a rough idea since the used market can be a different animal where some higher end instruments can go for ridiculously low prices at times (discontinued models or devaluation each time an instrument exchanges hands).
I agree with the rest, keep the the Prestige - but I see you've already decided
The BTBs are nice instruments but they're very different from the SRs. More aggressive sounding, chunkier neck. But they're well built, even the lower end models (pretty much the same with other Ibbys with solid workmanship).