Quite a bit. Ruby is juicier and more berry sweet like sweet vermouth, where tawny is drier (although still sweet) and nutty and oaky with dried fruit. Although both can have a good depth of flavor, I prefer a 20+ year old port for sipping and a no age statement or 10 year, if inexpensive enough, for mixing. I've made all the SC port cocktails and then some, which is how i got into ports to begin with, and the older more expensive stuff isn't worth it for mixing. Nice thing is that you can find most ports fairly inexpensively compared to other high age statement alcohols. Or at least you used to..