I've had success using both pieces from the same manufacturer as well as mixing/matching but one thing I've always thought that a manufacturer who "voices" their gear to have a desired outcome no doubt does so by using their own matching pieces. So in theory if you use both pieces from the same builder then you should be getting what both pieces were designed to sound like. This does not mean that using an amp from one builder and a preamp from another won't sound as good and possibly better but it may not sound as the builder had intended it to.
In the end success matching preamps to amps has as much to do with properly impedence matching as much as anything else.
In the end success matching preamps to amps has as much to do with properly impedence matching as much as anything else.