I am about to purchase an 8 quart stock pot. The first option is a "tall and narrow" like a cuisinart or kitchenaid or calphalon. The second option is a "wide and short" like an all-clad-type (you know how those all clad pots look). Which would you buy and why. Apart from shape, what other things should I consider to maximise the performance of the stock pot, e.g. material - is copper a necessity, etc.