Not sure I understand the reasoning behind the question... dif. faced hammers are used for dif. applications. That's like asking which you like better, pliers or tin snips.
As mentioned above, smooth face are good for finish applications (siding, interior molding), waffle face are a better choice for rough framing applications.
Mac
Edit to add: Framers are more likely to find themselves in a position where it's more difficult to swing straight at the nail (hanging over a rafter tail, in the middle of trusses, hanging off a ladder 20' up) - any help from the hammer head is great...