I play with an ESP MV-200 with Seymour Duncan pickups (SH4 at the bridge, SHR1 at the neck) straight to my Formula, then I send the entire signal through my G-Major (in serial...the G-Major colors the sound just alittle bit, nothing very noticable though, and I notice the slightest changes) then to my HUSH (not really needed, neither the Formula nor the G-Major make hardly any noise, but there's always alittle hum...) then to my Mesa 2:100 and out to 2 Marshall 1960B cabs. I control it all via Voodoo Lab ground control, and the G-Major switches the channels on my Formula (very nice!) so setting up patches is a cinch. The Formula alone dishes up fantastic low end punch and distortion (I don't really use any clean sounds, when I switch channels I basically just change to something with alittle less gain) however I load my signal with delay and reverb which takes alittle of the punch out of my signal when it hits my cabs. This I plan on fixing with a BBE sonic maximizer, which I've only heard great things about, and I think will really put my sound over the top. I like playing loud and heavy, as close to thunder as I can get, and the Formula meets my demands.
So far no problems, but I've only had it for 2 weeks. I got it used through Guitar Center, as it is now out of production apparently and they only had like 2 left in the country, and this was the best one (it was in the Virginia Beach store rack). I guess I'd say very reliable, as it has a few scratches and dents, and yet still sounds amazing, but I couldn't say from experience.
As I've said, this thing is awesome for loading up on heavy crunch and pouring out pure metallic balls. I'd definitely get this unit again, if I could find it in good condition. I can't think of one thing about it that isn't superb, except that it's being DISCONTINUED! I had a SANsAmp PSA-1 before I traded it in for this, as I was unsatisfied with the sound from it, and I remembered really liking the Formula when I played with it a few months ago. My only beef was that it didn't have MIDI switching, but that was solved by my G-Major! The more and more Mesa stuff I hear the more I'm attracted to their gear... the 2 pieces of their's that I have now are amazing, and I see myself loading up on more of their gear when I have the $$$$. This is a real preamp, with real balls, and real tone.