I never owned or even played the "real thing", but I have built
two Rat clone pedals from BYOC "Mighty Mouse" kits--one for myself with their original kit, and a second one recently for Sunvalleylaw, using the new-for-2008 v.2.0 kit. You can read about each at these two links, which also contain links to audio clips:
I love the one I have--it's just got that quintessential 80's distortion sound to my ear, and it will do the Clapton neck pickup/treble rolled off "woman tone" like nobody's business. Sustains for days. It's also not overly trebly & harsh on the high end, like many distro pedals sound to me. This older BYOC kit also incorporated a "diode lift" mode that basically turns the pedal into an opamp boost pedal; it still has a fair amount of gain-based distortion, but not nearly as much as the stock Rat setting. The kit also adds an "overdrive" mode that utilizes the less severe clipping set-up used by the Tube Screamer pedals & their many derivatives and copies. Mods that I added myself included switchable stock silicon diodes and red LED's on the main distortion clipping stage, and another known as the "Ruetz mod" (named after the originator) that reduces the gain and flattens the EQ profile with the flip of a switch. So lots of tonal options in addition to the classic Rat sound. I use it constantly.
But if you want tonal options, the new v.2.0 kit I built for SVL is just amazing. The posting I linked above describes it in detail, so I won't repeat all that here, but it has 6 different clipping modes--3 distortion and 3 overdrive. I modified the two clipping stage components so that each group of 3 includes silicon diode clippers, red LED's, and FET-based clipping (all the rage with the "boutique" pedal crowd). And I threw a Ruetz switch into that build, too. I liked the incredible range of tones on the finished pedal (12--six clipping settings x Ruetz switch off or on) so much that I've seriously been considering selling my original build and getting one of these--it's
that good! But I'll let SVL chime in here, because he's had a lot more time to fool around with it by now that I did!
Oh, yeah--built, decaled & painted for $125 + shipping, US & Canada only.