Here is an analysis of my success in commuting via bike all year.
In the summer I can ride with less clothing, but when it gets warm I need to bring a change of clothes. My bookbag (with laptop not trusted to panniers) presses on my back adds to my warmth. Still works alright, but a tiny bit awkward when arriving for meetings not at my building.
Winter- the rainpants and jacket I purchased over a year ago are still great. The pants don't breath, but it is a trade off for price. I rarely use the booties, because it is rarely wet and cold in Buffalo. I continue to love my J&G raincoat (breathes) and leave the pit zips open most of the time.
The steel studded tires were okay, but I would suggest people get the ones with studs down the middle, as well as down the edges. If you are going to slow yourself down, you may as well get good traction on ice as well as slush. Fenders make an enormous difference in how dry you stay.
Time- it takes me more time to get to work because I must dress for it/ stow a second set of clothes.