Why is Extra Punctuation better? Because Zero Punctuation is hamstrung by several things.
The fact that ZP is a video series, and especially that it's one that originated on Youtube with its eleven-minute length limit. It's a lot harder to go into depth with something when your videos are expected to be roughly five minutes long.
The fact that ZP is a comedy series. Not saying that comedy can't be informative and insightful, but the requirement to make jokes reduces the number of informative things he can say. Because there are things that need to be said that just aren't funny.
Similarly, people expect ZP to be as negative as possible, and Yahtzee himself has said that saying good things about a game isn't funny. Basically, Extra Punctuation actually gets to be honest.
People basically rant constantly at Yahtzee to review something despite him not really wanting to. I think it makes him vindictive. See: Super Smash Brothers Brawl, Final Fantasy 13.
Extra Punctuation is better.
Why is Extra Punctuation better? Because Zero Punctuation is hamstrung by several things.