I found season one to be quite bad but most of season two's episodes were entertaining. Then season three started and I think it is really quite terrible. I've had one or two light chuckles per episode and there isn't anything interesting in-between.
Their 'jokes' remind me of a bad Adam Sandler movie. They spend way too long setting up the joke and then too long after the joke going "get it, get it? No? We'll tell it again."
"Oh, no they are planting things right next to where Clarkson parked. I hope he doesn't drive over their garden!" Sheesh.