First of all, it sounds great. Bit darker and less gainy than Blues Driver, though. HOWEVER. If you look for a battery-operated OD, look somewhere else - the screws are terrible quality, very soft. I changed battery a couple of times and screws just got flat. One was nearly destroyed and I just couldn't open the back plate. I've been using other pedals, and these screws are absolutely the worst! I mean, if you allow battery operation then at least use quality screws!
If you gonna use it with power adapter it should be fine I guess. OR get better screws immediately after buying it.