I've never been a fan of first-touch, last-touch, or first+last-touch attribution. Who's to say which campaign truly impacted the creation of the opportunity? We look pretty much exclusively at the campaign influence report, and we summarize by things like # of opps influenced, total revenue influenced, average opp size influenced, etc. This allows us to make sure we're not letting one huge deal impact how we're seeing the data, and it gives us relative success of campaigns, so we know where to stop spending and where to double-down.