If you take some precautions, its usually not a problem. If you have a tile drainage system for the foundation, connect the egress well to it. You can do this by just digging hole down to it and refill with gravel. In new construction they typically tee off the pipe and run a small drain. If no system exists, at least slope the bottom away from the house with a small gravel resevoir on the end.

I read somewhere that the window size codes were set so as to enable a fire fighter with airpack to pass through the window.

I put this in another post, byut we LOVE our scapewell window well. Our contractor would not put it in unless we bought the cover also. Even when it pours, no water gets in. The cover actually is a good thing since our neighbor's can't look directly into our basement from their deck, but it still lets all the light through. You just have to clean the cover seasonally.