One angle that hasn't been mentioned yet is efficiency. There's a fairly well known optimization (permutation vectors) that allows (defmethod foo ((x bar)) ... (slot-value x 'quux) ...) to be very efficient as long as X isn't assigned to (and as long as there is not SLOT-VALUE-USING-CLASS, etc) -- not as fast as plain structure accessors, but basically at the cost of two memory indirections. A laugh compared to calling a generic accessor. That said, I *think* permutation vectors can be extended to accessors as well, but I don't know how commonly that is implemented (eg. SBCL at least currently doesn't) -- whereas most(?) implementations, particularly those deriving their CLOS from PCL probably implement the basic permutation vector optimization. Of course, readability and maintainability trump efficiency any time, as long as the code if efficient enough for its intended purpose. Still, something to be aware of when choosing between accessors and SLOT-VALUE. Cheers, -- Nikodemus