Sound — 8
I currently run my guitar, a Modded Yamaha RGX420s into a Dunlop ZW-45 Crybaby into the Drivemaster and then into my amp. This pedal is extremely versatile, lots of Marshall-y tones available from Blues - Hard Rock right through to Thrash (and heavier) Metal. This is basically a JCM800 (or close to) in a pedal, I got it to imitate some Iron Maiden tones, which it does perfectly. I nailed some Megadeth tones recently too. I primarily purchased it for Metal but, was quite suprised at how well it achieved the other styles I mentioned earlier.
Overall Impression — 9
Thoroughly impressed with this pedal, they occasionally pop up on Ebay but have been known to go for anywhere between 30-60, I got mine for a steal at 15 secondhand. Really worth it if you can find it for under 30/40 anything higher than that and you may want to look elsewhere. Overall this pedal gives the guitarist a wide range of tones to play with and in my experience it certainly kicks the tit's of some of the OD pedals currently on the market.
Reliability & Durability — 10
This pedal is easily 10/15 years old and is still working perfectly. It's built like a tank made out of metal (no shitty plastic here! ) however, when I purchased it didn't have a battery cover, through online research I've discovered these were very flimsy and broke easily so that's a downside I guess. It's true-bypass and doesn't effect your tone when turned off, I personally use a power adaptor but will obviously run off 9v batteries, in my experience batteries will last quite a long time, just remember to unplug the input jack when not in use or it'll drain juice. Other than that, this pedal won't shit out on you during a gig/practice.
Ease of Use — 8
The Drivemaster is a british-voiced (Marshall... ) Overdrive pedal. It can be used as a standalone pedal for Overdrive tones and can also be used to Drive an already dirty amp. Extremely easy to use. 5 pots; Gain control, 3 band EQ (Bass - Middle - Treble) and a volume control. Like all pedals it'll take 5 minutes dicking around with to get the sound you want.