If you like the Marshall tone, get a DSL401. I got my Engl thunder had and cab used for £550. You could probably get a used 5150. Or Line 6 HD147s go cheap used on eBay.
I spent some time using a VS100 and an AVT112 combo at a friend's house, and I could never get a decent sound out of them either. They always sound really thin and lifeless imo.