I guess for the money its ok.
But the one thing you want from a chrono is accuracy. Which this just doesn't seem to have.
Compared it against 3 other chrono's at my local and they all gave a pretty consistant (within 10 fps) reading. But my ST-08 gave 33-37 fps above them all! I seem to get many random fps readings and it alo seems to get stuck reading the same fps shot after shot... even though you know they cannot all be dead on the same fingure.
Maybe it was just mine, but i guess you get what you pay for. As a rough guide... possibly