Welcome to EQ-101. Let me tell you what nobody else on this review has talked about... CUT, CUT, CUT!!! This is the basic of how-to-EQ. you can cut to -15db, which is alot. Try not to boost any, unless you really need more than 15db of difference between the cut and boost freq.
Also, BOSS pedals are LOW-INPUT devices, meant to go between the guitar and the amp. Only high-voltage devices, like rack-mounted effects, POD, and power amp heads should go in the amp's effects loop! Notice if you put any BOSS or a CryBaby Wah in the amp's send/return, you will get noisier, sometimes muddy sounds.
Third, this EQ is meant to change the shape, not the volume of your sound. If you boost any frequency or master level obscenely, you will get obscene, "bad" sounds. If you want lead/rhythm boost, that's what the knobs/PU-switches on your guitar is for (I shit you not!). The best tonemasters, from Clapton to Iommi, know that the key is to be SUBTLE and SIMPLE.
Having said all that, I own an SG, a BOSS BluesDriver, MXR comp, and CryBaby. My amp is Fender Princeton, 60W. Like I said, the sound you create is up to you. There are gazillions of ways to change tone, or reduce noise. I can get anything from Metallica to Albert Collins, even Jazzy tones. The set neck construction and puckups of SG makes a creamier, less harsh sound that sustains nicely, so I can't get an authentic Fender sound, but I prefer the SG's smoothness much better. I can get trebly or middy without sounding thin or harsh. The GE-7 EQ makes almost everything possible. Then again, if you want a strat-ish sound, go buy a strat.
The only way to really test this is to beat it with an axe, since all BOSS are built like tanks.
Note that it is physically/structually impossible for anything like those tiny EQ knobs to withstand Townsend-style kicking and smashing. The knobs are meant to be tweaked, not bashed. If they fall off, go get a superglue. Better yet, treat any gear with reasonable respect.
I LOVE this pedal, it more than triples the versatility of my guitar setup. But in the end, I only use what i need to. I try to let my guitar's character come through as much as it can.
By all means experiment. But when it comes down to showtime, KISS-"keep it simple, stupid." I sometimes don't use this pedal. I wouldn't die if it stopped working during a gig (VERY unlikely). Sometimes the sound of your guitar plugged straight into a combo amp is the best sound. Stevie Ray recorded his best album in 72 hours with a Strat and Twin Reverb amp.