The problem with all the monitors we got were that they all seemed to confirm that my wife was no ovulating. It became one long stressful waiting game. She would only ovulate during periods of stress free relaxation, where we are feeling good about life, and about our future. Our doctor said we have four kids, and it is more than likely that she has only ovulated four times since we got married.
Clear blue is the best product, and can be used in conjunction with Chreighton. I believe the method is called Marquette. The only issues with this product are: 1- It is expensive, 2- If you have a long cycle, or multiple hormon peaks, it stops working after the first peak. My wife usually had two or three hormone peaks.
Basically with Clear Blue, all you have to do is pee on a test stick, and the monitor validates you fertility level, and indicates where you should try (or conversly, not try) to have a baby.
OvaCue is a little bit more complex. It measures your fertility rate by giving you a set of numbers that you have to graph. (Actually I think there is another version that acts more like Clear Blue, but it would not have worked for us because of our long cycles). My wife didn’t like it because it is a bit more invasive. She would have to insert a probe into herself, and she just didn’t like it. It had more to do with her personal sense of decorum I guess. If you are not opposed to this kind of thing, then by all means, try it.
Hope this helps.