For grilling, I PREFER lump because of the total absence of binders that don't help in any way when juices hit the coals, especially if basting the meat like with Cornell chicken. (Speaking of grilling chicken, if worried about lump being too hot, avoid mesquite. Also, shut the air back and keep the lid on the kettle as much as possible between turning.) I shut down the fire after burning off the grate and use all the decent sized pieces left next time as well. I don't bother with saving leftover briqs, though. They just seem to fall apart and not burn near as hot or long next time.
You mention Stubbs though, so I'll tell ya what. I don't think you can find a better fuel for the wsm, at least not for the same price. I've only had one bag that acted funny, and I've used it quite a bit, especially for long smokes. I'm not worried about ash suffocation and it gets up to temp plenty fast compared to other fuels. With lump you have to pack it REALLY tight to get as long smokes as with Stubbs, (but I still don't think it'll last quite as long as briqs going from my own experience.) However, I can use a whole bag of STUBBS using my el cheapo Brinkman water smoker charcoal pan ($6 at Academy Sports) and still have enough room for my wood chunks.
I don't think that Kingsford lasts any longer than Stubbs, either. The best thing Kingsford has going for it is their huge marketing machine, and I only buy it when it's a loss leader at Home Depot. I use it for short smokes and grilling tube steaks, hamburgers, etc.