The regular show is the best comedy news panel show around - much better than Mock the Week since Frankie Boyle left, and better than Have I Got News For You which is too dependent on the guest presenter and relies on Ian Hislop and Paul Merton to provide the improvisation, the latter of which is a shadow of his former self.
Sean, Jon and Jimmy are a good combination. It doesn't matter who the guests are, the show can still be hilarious because of those three discussing topical things.
However, 8 out of 10 Cats Does Countdown is long past its best. Joe Wilkinson has never been funny. The best part of the show is actually the start when they introduce the guests and have a bit of a chat. Once they actually start playing, every episode is kind of the same. Jon could win if he wanted to, but he instead purposefully guesses words that aren't real (and aren't funny). Sean looks exasperated the whole time because he doesn't like having his intelligence questioned, and he would actually really like to win, but when it looks like he won't, he also goes for silliness.
I'm surprised they keep making new episodes when there's nothing new to be had from them. They always try to shake it up a bit with Jimmy doing silly things while the clock runs, but it's not enough to make a 45 min show worth watching. The humour of it ran dry after the first six or so episodes, and now they're just running it into the ground doing the same thing over and over. The initial comedy was based around parodying Countdown, but once the parody becomes the norm it ceases to amuse.