His acting ability...
Personally, I think that Paul Wesley is a big talent. I'm British, so I've only seen him on the stuff we get imported from the US - i.e. Smallville and The Vampire Diaries. He's especially good on the latter Programme, particularly as that's the only one he's been on for a long period of time.
During series two, his performance in the episode in which Katherine compelled Jenna to stab herself after finding out that Stefan and Elena fabricated their split was stellar. The scene in the same episode where they genuinely broke up was heartbreaking, and both Paul and Nina pulled it off brilliantly. And as for his Vampire Diary video diary appearances - quality!
So yes, generally Paul is a brilliant actor who defiantly deserves more credit than he gets.