I used these. Best of both worlds?
Ringshanks are great for lots of things, but their additional holding power is lost when driving into end grain as on a box. They are a still a good choice as they run a narrow shank and relativley wide thin flat head....like a box nail, which nearly eliminates splitting
I was thinking about the deck screws with the tapered shank which make it easier to split the wood but don't know if they make a good coated flat head screw .The spiral nails will work good also and no worries of splitting but I like the way screws suck the joint tight.