I like my Windsor pan and like the job it does reducing sauces, stocks, etc. I also have a saucier and have used it to do the same thing because it's bigger than my Windsor pan. Never compared the two side-by-side but, then, I would have to have two pans of equal capacity and equal amounts of liquid.
Hmmm. This might be a good excuse to buy a new pan.
Michael, one thing I do to ensure I've reduced my sauce by the amount I want is I have a stainless steel ruler I keep in my utensils crock. When I put the liquid in my pan I measure the depth of it. Say it measures 3 inches. If I want to reduce by half, I know I'm there when the liquid comes to the 1 1/2 inch mark. This is almost exact if you are using a straight-sided pan. A Windsor pan has slanted sides, so your reduction would be approximate, but close enough IMO.