Clamp-on power meters

Does anyone have any experience with clamp-on power meters? Are there any that work on normal power cords or do you always have to measure a single wire (usually at the circuit breaker)?

Single wire, somewhere, if I read my instructions right, for AC as well as DC. For AC, that often translates into the panel.

Do you have one (clamp meter)? The good ones are spendy. I needed a DC-capable one to put together a power budget for the WRX, and I finally found one for $50 at Sears. The selector knob is a bit rough, but it seems to work. Oh, for a Fluke!

I've borrowed one at work. I was trying to use it to determine the real-world load I was generating with some servers, but it didn't work on the normal power cable. I had to go to the panel and measure there. But that's not as granular as measuring each cable. I had to estimate that each one was drawing about the same amount of power.

The one I'm using is pretty much of Sears quality, I'm guessing. It's an Amprobe analog deal. It looks like it was made in Taiwan by retarded monkeys, but it seems to work.

Couldn't you hack up a spare cable and use that to temporarily power the servers? I know it's a PITA, but it should work.

I thought about that, but the whole point of the clamp-on is that it's non-invasive. You can measure without having to disconnect stuff. And while some of the machines I wanted to measure have multiple power inputs, many don't.