A lot of people (not just here) had a lot of bad things to say about Vance when he was picked. From what I can see, out of the 4 individuals on the two major party presidential tickets, he is the most intelligent as a politician, best spoken, and most likable. As a VP candidate he likely won't move the needle a ton in either direction, but I think he was a good pick for Trump.
The problem for DT/JDV is the (D)s are running a campaign where the media is doing the heavy lifting for them and they seem to be giving the actual candidates as little opportunity to belie the crafted narrative as possible. Sort of a doubling down on what they did successfully in 2020. Trump and Vance might be fighting the last war, so to speak, using outdated tactics of getting out and engaging with as many voters as possible to go against an almost infinitely fungible opponent. Bold strategy by the (D)s, and they've got a good shot at pulling it off.