I've been using Rivera since 1998. I've owned the K100 Knucklehead (2), a R55-112, and now I'm down to a R30 combo. Riveras have a Marshally Channel 1 and a Fendery Channel 2 so you get the best of both worlds.
Early 90's versions are great. I've owned a number of them over the years including the Classic 100 head, and the C30
Great clean and great drive channels. They run HOT though!