I watch a lot of teams besides Barca...and their finishers are not as great as they seem to be. Falcao actually misses quite a few chances lol. I would agree that Messi is probably the best. If not him, then it has to be Ronaldo. His goals per shots ratio is poor because he takes stupid shots from long range. His finishing, however, is excellent. I rarely ever see him miss inside the box, unless it's a header from a corner.
Does nobody know what the question means? O-f-c it is NOT Messi, sorry. Best overall goalscorer? With everyone on form he's not even the most lethal finisher for Barca...
Finishing has as much to do with form as anything else. So the fact that the top forwards like Messi, Ronaldo and RvP hardly ever lose form makes them the best finishers.