I'm certainly not an expert on boots, but I can relate my own experiences. I own a couple of pairs of Tony Lamas with roper soles - polished leather. Because I have flat feet, I also use generic orthotic insoles - I keep meaning to get custom orthotics, but I can't seem to find the time or the energy to make the appointment with a podiatrist.
The boots are constricting for the first couple of weeks, and you'll find yourself not walking so much as sauntering. But once you break them in, they're utterly form-fitting. The knee and lumbar pain that accompanied long cases has entirely disappeared since I started wearing them, and they're comfortable enough at this point that I can sleep in them while on call.
Another advantage is that they can be worn as moderately dressy shoes, if you keep them polished and in good shape. They can be resoled and re-heeled indefinitely.
Buy your boots from someplace that specializes in that footwear, as the fitting is counterintuitive. The boot you want will feel much too tight when you try it on, but if you buy boots that feel comfortable in the store, you will end up with loose-fitting shoes later on.
As far as image: they sure are conversation starters. As long as you don't try to live up to the image of machismo or cowboy-hood that seems to come with the boots, it can be positive! Some of the nurses call me Doctor Boots - affectionately. I make no bones about not being a cowboy, not being from Texas and being more comfortable around cats than horses.
Any other questions I'll be happy to answer, but really, the best source of information would be people selling you boots.