I want to buy an amp that is fairly portable yet is loud enough to play with drums and guitar. Something more than a small practice amp but not a head and a stack of cabinets either. I've tried the SWR Working Man's series and was impressed with the sound and the features that would be useful on the studio. I'm also interested in the Carvin RB 600 2x10. How does it sound? Could anyone recommend anything else. Under $600 would be great.