Retsupurae used to be great, but now they're pretty hit and miss. Some of their "Kickstarter Nonstarters" videos are funny, but for the most part they've more or less devolved into "Game Grumps 2: Electric Boogaloo." The last thing they did that I really enjoyed was their Ambition series back in 2013.
DashieXP/DashieGames is, in my opinion, the worst gaming channel out there. The dude's basically an even more obnoxious version of PewDiePie. Literally every goddamn thing out of his mouth is screamed. Also, while people give Pewdie shit for milking Happy Wheels long after that cow had given up, he eventually acknowledged that it had run its course. Not Dashie, though.
Any channel related to Gamergate. It doesn't matter what side they're on. If they're involved with Gamergate, they're guaranteed to be teeming with retarded autism.
AVGN's channel's also gone to shit within the past few years. Mike Matei's pretty much run everything into the ground.