Anybody tried both? I have a free rack space and I am willing to pay the extra cost of the Pro Rack but if I can get by with the pedal version I'll be much happier. I need a way to avoid high gain squeal at stage volumes mainly for use in my lead channel. We've decided we're going to do some Metallica covers for the end of the gig to end things on a high note. After all those first three albums are between 25 and 23 years old now so they qualify as classic rock. I an get a an insanely convincing tone out of my Mark IV but it tends to squeal during breaks. I'm not willing to sacrifice tone and I have looked into the alternatives but these two seem to be the best bet. I have a free rack space so that's not an issue. Thanks.