WDG said:
...As far as stability with the monopod, I find that I get fairly good control by having the stick angled just a bit forward, pressing the camera to my eye and leaning into it some...
I also read about this technique, and find it works very well for eye-level shots, only way to go, really.
Mono-pods eliminate the small shakes you get in your hands, and from mirror-slap with reflex cameras, but below 1/15th sec. the movement of the mono-pod itself, however slight, starts to become noticeable. I find they are best used in situations where there is enough light for hand-held photography, but you want the extra sharpness a tripod gives. For low-light situations, I still use a tripod.
My main issue with tripods is the attention they attract, and the fact that they are forbidden in many places. When I'm carrying mine, I get lots of comments, and sometimes feel I'm carrying a sign that reads "This person has something worth stealing". When I'm carrying a mono-pod (basically a 2ft piece of metal pipe), people may still look, but keep their comments to themselves.
I never considered a mono-pod until I bought a Bronica-S2 (a four pound 6x6 SLR), and quickly learned that while it is possible to shoot it hand-held, it's not especially pleasant and there's no way I'm going to carry a tripod everywhere.. I have also come to use it a lot with my Nikon F2.
For hand-held daylight photography, I've found that any 35mm RF camera with a good lens will give results almost as good as a tripod mounted SLR, and that's why it's my camera of choice for 90% of what I shoot.