To me the Heavy Machine and Megalith are different, but both are very good, intense, bass heavy fuzzes. If OP likes the Heavy Machine idea it's worth it to also consider the Huge Box II, same fuzz just a simpler tone section and a little cheaper.
Everything Alan makes are original circuits and point to point wired, not saying they aren't expensive but they aren't a rip-off either. They're all bigger than they need to be, and I've seen a few nice rehouse jobs to get them smaller but that would only add to your cost.
That's my story and I'm stuck with it.