Robert - great question.
When I first got my WSM I used briquettes exclusively because it was supposed to be more consistent, easier to start, easier to pack in the charcoal ring, etc. It seemed like a no-brainer.
However, I found that regardless of what kind of rub I used on my ribs, butts, etc - they all ended up with similar flavor due to the briquettes. I got anxious one afternoon and picked up a bag of Royal Oak lump from Walmart, and haven't been back to briquettes since.
The lump seems to have a much more pure flavor that briquettes, and doesn't impart the flavor the briquettes were doing, probably because there weren't any additional additives in lump like their are in briquettes.
Despite what I had read about lump being harder to control, burn hotter, etc - I actually found it easier to use than briquettes because the lump really reacts much quicker to vent changes, which I loved. It doesn't have the funny smell at startup either (a huge plus to me). Once I used lump you can really differentiate the rubs used on different ribs, instead of having to mark them or remember where you placed them, etc.
Oh yeah, and its cheaper too!
Give it a try if you haven't. Granted I still keep a couple bags of briquettes around that I'll use to start my minion method for doing smokes, I.E. will pack the ring with lump, light 15 briquettes, and scatter them across the top. Briquettes still have their use in my opinion, just not as primary source of fuel for smoking or grilling.