Both are terrible, and started going downhill around the same time, racing each other to the bottom - beginning in 2005 (when you started getting shows like Deadliest Catch and Decoding the Past, which became the prototype for many future series of increasingly less "reality"), and then full force by 2007 where you start getting too many shows to name.
One thing that drives me crazy almost as much as the blatant pseudoscience presented as fact is the extensive acting presented as reality. I mean, okay, I get it, a purely "reality" program is pretty much impossible, the very requirements of filming it make it so. Even in stuff like Les Stroud's "solo" work he always had a base camp just a couple kilometers away from him and stayed in communication with them by radio. But now the stage guidance, product promotion, and "weekly scripted adventures" have gotten so absurd and obvious, they don't even try to hide it any more. I thought that they couldn't get any lower than the bogus survival show Man vs. Wild (where the host pretended to be living in homemade shelters and surviving off wild food, when he was actually staying in luxury hotels and show consultants prepped everything from making "rafts" for him to releasing "wild" animals for him to catch). But now almost all of their shows are like that or even worse. And the product promotion, my god - have you seen the Pawn Stars plugging for Skype? If you're going to have your "reality show" stars plug a product in your show, at least get people who can act.
The changes are so visible with time, too. Take Mythbusters for example - watch some of the early eps and compare with the modern eps and look at how much more is obviously staged acting with everyone reciting a script (not to the extent of Smash Labs, but still). Apparently Discovery Communications has decided that this is what people want to see - bad actors going on "daily adventures" and having "witty banter".