My wife bought me one of these for my birthday (couple weeks ago). I got to use it for the first time on the weekend and thought it was really great. I tune really quite well by ear, but it takes me forever and I hate doing it. I found that I had all my lugs within 2 Hz of each other already (in most cases 1 Hz). That little bit of fine tuning I did with this made a HUGE difference. I think it is a great device.
That all said. I would think if you can't get it in the ball park of the right spot, it likely won't help you really improve the overall sound of your kit.
"The right to be heard does not automatically include the right to be taken seriously" -Hubert H Humphrey