The Trainwreck Express is killer! A guy on MLP builds them also as well as other pedals
From what I gather, there is two adjustable waveforms (highs and lows) that the BBE isolates allowing you cut/boost as to your listening/recording needs. A eq only manipulates boosts/cuts frequencies in one 2 channel wave form. I am sure others could explain the process. It's almost like a dynamic recovery unit. It does bring whatever source fed into it alive
EDIT: I miss my old Fenders from when I was a kid. I had a Princeton Reverb, Deluxe Reverb and a Super Reverb
I had a Super Reverb back in the late 70's. It was the master volume model, and I remember it was a cool amp. Had the CTS speakers in it. I missed it so much that I bought a 1969 drip edge Super Reverb back in 1998 or so. Kept it 13 years and sold it for a $400 profit. That was a great amp, but I have a Tweed Bassman RI that I had modded to REAL 1959 specs that sounds even better, so I let the SR go. The Bassman RI amps have slightly different tone control component values, and the presence control is different too. Plus, the early RI's didn't have adjustable bias, so I put one in. Made a big difference.
I now have a 1967 blackface Deluxe Reverb that I got at a pawnshop for ...get this...$250 back in 2002. I put a Warehouse speaker in it and saved the original Oxford. It sounds really nice, and it's loud enough for what I do anymore. If I need to get loud, I go to the Bassman or to a Sovtek Mig 50H that I run into a Marshall 4x10 or a 4x12. The 4x10 Marshall sounds really nice and it's easy to carry too.
I never have had a Princeton though. Those are great little amps, always wanted one.