It depends on the video. If I'm just searching through random WWE videos, I'll leave it on standard. Now, occasionally there will be a match worthy of the full screen view, like most recently, Antonio Cesaro vs Sami Zayn in their 2 out of 3 falls match on NXT.
While there are some other videos I have to watch on full screen no matter what. Like TotalBiscuit's videos, TubbyEmu's videos, etc.