As others have noted, Vance is really good at this. Walz came out of the gate bumblin' and stumblin'. Sometimes he said things that didn't make sense, or used words that people don't normally use, like saying 'current' in place of 'present.' There were times when I didn't really understand what he was trying to say. I found it annoying that he started so many of his answers with 'Look.' I find that particular vocal mannerism off-putting and a little bit condescending. His constant use of 'folks' in place of 'people' is also annoying to me (i am aware that perhaps others might consider it endearing).
All this is to say that I could easily listen to Vance talk for an hour, but an hour of Walz might drive me batty.
But i'm voting for him, anyway. I think he is correct on more of the issues, so I don't really care about annoyances or his personality or his word choices. But there may be voters out there who are not issue driven.