Peteb, I would consider the Blues/Hot Rod amps to be at the bottom of the price range for Fender tube amps. The Reissues are the midrange, with the Pro Sonic and the Custom Shop amps at the top. The Pro Sonic started out in the CS. Fender has built exactly one amp with the construction method of the Pro Sonic...none other is built in that manner. The Reissues are not as well built. As for Mesa being the progenitor of Dual rectifiers, that is not so. Fender had dual rectifiers in the 5E8 Twin in 1955...and one could be pulled to gain different response. Back to the subject.... collectibility has only one driving force...demand. I don’t see why that would occur; but if it does and I can buy one cheaply and sell it to a ‘collector’ for profit, I would not argue with the reality. I don’t foresee such a reality, but we people are strange creatures who do strange things, right?