For straight up brootal out of the box, the 2 and 3 channel rectifiers are definitely more aggressive. As mentioned above, the Roadster is voiced darker, so running straight into the amp, the regular rectos have a lot more cut, making them sound more aggressive.
Overall though, I still prefer my Roadster. Like Nitrobattery, I too owned a 3 and 2 channel rectifier, and I wouldn't ever go back after owning the Roadster. Perfect Mesa amp IMO. With a boost out front, it is tighter, and more natural sounding than a regular rectifier, while still being CRAZY brootal.
I'll post some clips soon. :twisted: