I love Demetri Martin’s standup, it’s entirely different than your standard “oh ain’t this situation funny” comedian. I agree, though - Trendspotting isn’t all that great.
Sharing your embarrassment with your audience really isn’t a great talent. He was funny, but his material always sucked. He would have been better off trying for good jokes. 
The Daily Show is the same as it ever was: it has up and down periods depending on what’s happening in the news. The current correspondents still aren’t a great batch - Corddry is the most consistent, but I feel like he isn’t around as much lately; Jason Jones is alright and I like John Hodgman; the rest I can do without - but why give up on the show altogether?