I don't know about you guys, but I certainly feel that an SLO (on the overdrive channel) and a 5150 (on the lead channel) can sound quite similar. But by similar, I mean similar in terms of them being thick, compressed, (relatively) dark amps that have that condensed mids kinda high-gain sound. They can both sound quite different, but there's definitely common ground. Having said that, I'd say the 5150 sounds more raw and wild, whereas the SLO sounds a bit more refined and versatile. The other two channels are quite dissimilar IMO, and I don't think a lot of folks use a 5150 for the first two channels although the SLO has way more useable clean and crunch channels. But the third channel on each of them does have similarities.