Depends how you define "best". I consider the RAS rocker arms to be the very best choice for street driven roller cam setups. They are strong and they won't break like aluminum rocker arms after X number of cycles.

For drag racing then something like the T&D or the Jesel rocker arms would be "best". Also, the RAS only come in 1.50 and 1.60 ratio so if you need 1.75 then the RAS isn't "best" anymore.

RAS only sells their stuff direct so you have to call them and order the parts. They do not sell thru any distributors or dealers. They only make the investment cast 440 rocker arms once a year so when they are gone they are gone. You'll have to call them to see if they have any on the shelf or not at the moment. I saw a set in the parts for sale section last month so you might get lucky there.