General Grievous was really cool in the original Clone Wars cartoon and Star Wars: Republic comics. He was a serious kick-ass threat, and you knew that when he showed up some Jedi were going to die.
Then came Revenge of the Sith, and as much as I love that movie, General Grievous was just another henchman. I get the impression that George Lucas intended him to be more like one of Ming the Merciless's toadies, and if he had a mustache I'm sure he would have twirled it. And that's all well and good, but after the huge build-up he got in the other media... well, the film version of him was a bit of a let down.
So I'm rather pleased that this version of Clone Wars is returning him closer to his former glory. He gets caught rather easily and loses his legs, yet still manages to be threatening and kill a few clones. (And the way he was crawling around on his four arms made him come across as very spider-like, which really creeped me out. Very well done.)
And okay, so he spends most of his time hiding and attacking the Jedi by remote... but he still came across as menacing, creepy, and dangerous. And when he went out to fight Nahdarr Vebb face to face I felt like I was seeing the old Grievous again.
Long story short, two Jedi and six Clone Troopers went in, and only one Jedi came out... and he barely got away with his life. That's pretty tough. I feel like this show has taken the tough pre-movie version and mixed it with the slimy, cowardly lack of honor of the movie version. All in all, I think it works and makes Grievous an enemy to be feared again. (The only downside being that we know he can't kill certain Jedi because they don't die until Revenge of the Sith. But you get the idea...)