They're pretty different to play feel wise, the Splawn has a cool (THWACK) kind of attack to the chuggy stuff, kinda like a Plexi to me, and the low end is really big. The Splawn also has loads of gain. I typically play the Splawn with the gain at 10:00. My Splawn Pro Stock also has 6550 so to my ears it's got a woodyness it it. Hard to describe...but yes since they're Marshall style amps, they are in the same zip code. The Helios is way more versatile since it's got 2 channels (barely messed with the clean) and lots of options to eq the amp.