I can't speak for the Orion, although I'd love to try one out sometime.
I have an Orange Rockerverb 50 and Orange 4x12 and love it, really nice crunchy sound, has a vintage vibe and can do modern as well. Definately worth spending some time playing with Orange gear, might not be your thing in the end, but they are good amps. I use a Hotplate with it, yes it alters your tone some when you increase the attenuation, but you can still get some good sound and still hear the TV.
Can't speak for Marshall as I've not experience of them.
I recently bought a Diezel VH4 and this thing is AMAZING at low volume, ok no amp is at it's best unless you put some power into it, but the Diezels work well at home volumes. The new schmidt might be worth a look, it's 15/30w, so that might fit the bill. The Einstein comes in 50/100 versions, that might also be worthy of a look. Diezel ain't cheap though. :(