In terms of which is tighter; the Nailbomb without a shadow of a doubt. I found the A-Bomb to be VERY tight and aggressive and while there are times when I could certainly use the tone and love it, I felt it would be better suited to something with more mahogany in it. Personally I didn't find it particularly versatile at all but it seems to be a pickup that either works or doesn't. From what I've read and experienced, it can be a bit fussy as to which guitar it works in. The Holydiver is tight enough but I'd describe it as highly articulate because its tightness doesn't dominate in the way it does on the Nailbomb. The Holydiver is an extremely versatile pickup. It can work in either mahogany or alder and has enough aggression for Rock/Metal while also being able to roll back into other material. I play some Blues on mine too and can use it for every song in our set, running from 'Bad Moon Rising' to 'Paranoid' and modern stuff like COB.