Windsor works and makes fine ales, but it really depends what you are using it for.
It doesn't attenuate quite as highly as other strains which can leave you with a malty beer - but depending on your brew and your tastes that may be exactly what you want.
My biggest issue with it is that it doesn't flocculate as well as other strains, so it takes a long time to settle out even after fermentation is done. Clarifying agents like gelatin can fix this too.
Nottingham yeast is pretty popular as it has a higher attenuation and flocs better than Windsor. I'm getting a NB kit next week that comes with Windsor yeast but I will probably substitute a packet of Nottingham just for those reasons.