you watch him do standup and leave thinking he was funny, mission accomplished. Not every comedian has the same approach to making you laugh. For some it's all in the writing, and the material itself is funny as heck. I've watched clips of some comedians who were working out material and the jokes themselves were so funny that the delivery didn't even matter - in some cases they were even sloppy with the delivery because they were working it out.

But then there are some comedians who are just funny and the material doesn't matter. They could go on stage and do the ABC's and that ish would be funny just because they are funny as heck. That doesn't mean they aren't good at comedy because the material itself isn't good. If they keep you laughing - whether it's with voices, facial expressions, whatever, then they are good at what they do.