The SLO is pretty good. The crunch channel is a bit sterile until you get the volume up. And when I mean up, like 5 or higher. If course at that level its pretty loud. As RDodson just mentioned, the overdrive has a tubby low end. You also have to keep the gain low or it will be super compressed. The overall amp is scooped sounding in the mids so Vintage 30s do work well. Overall it's a great amp but needs to be loud to get the most out of it.
The 30 didn't do it for me. Too compressed and squishy.