obvious difference is that adblock decided to allow companies to pay them and not be blocked. clearly this is going to let stuff through it should be blocking.
for that reason alone, ublock is the way to go. it does not let folks pay to let their ads through.
there are things that ublock let's through that adblock did not though, so it is a trade off. for instance those annoying video ads that follow you around the articles here on tom's. adblock did not show me any of those at all. i did not even know they were on the site until so many started complaining about them. ublock does not load the video but it still let's the little screen chase me around the site.