i *think* (i could be wrong) that the fender is a "better" type of hybrid than the marshall. the fender has a tube power section, and at least some pre-amp tubes, while the marshall only has a solitary pre-amp tube. having owned the marshall (which was cr@p, i sold it) and having tried the fender, the fender did sound and feel more or less like a tube amp to me (albeit with some digital modelling thrown in, like the spider valve). the marshall didn't/doesn't.
btw, i think the blackstar has a lot of solid state circuitry in it too, but again, i think it has a tube power section, and one tube in the preamp. i think it does qualify as "tube", though. haven't tried it yet, unfortunately.
you're probably right about the cubes (i haven't tried the vox da5).