As with most people, I was skeptical of the CGI but I'm glad I decided to give the show a chance. In my opinion, it's one of the best cartoons currently on TV.
People may remember Bruce Timm from the Superman, Batman, Justice League animated series. One of the producers in this new series, he and the rest of the creators do not disappoint. Unlike the bulk of its "predecessors" listed above, GL: TAS is comprised of an ongoing plot instead of individual/ two-part episodes. Despite this, each episode always feels "complete" in its own way, wrapping up quite nicely (unless ending with a cliffhanger, of course). A big plus in my opinion.
Going along with the above paragraph, the plot-lines and dialogue in each episode are well thought-out and well-executed. There are only two events that I found forced:
1.) A certain romance that started at the end of "Fear Itself"
2.) What happened to Hal Jordan early on in the last episode (although "explained," the only purpose it seemed to serve was to give another character a more important role in the series finale)
One of the series' greatest standouts is its characters. The Main Cast is great and even the supporting cast has many quirks, thus keeping the story fresh with each new episode. Two of the main characters in this series are completely new, similar to the well-loved Harley Quinn of Batman: TAS. In my opinion, as well as what seems to be the bulk of the fandom's, these characters are a GREAT addition to the series. Some even say they "make the show worth watching." In a way, I agree.
And for any music-lovers out there, the soundtrack for the series is one of the best I've ever heard. Very epic.
Since people ALWAYS compare this show to Young Justice, I suppose I'll give my own opinion. Ready for blasphemy?: I like this show better than Young Justice. *Gasp! Instant Thumbs Down!* Don't get me wrong, I like both, but to me GL comes out on top.
I agree with everyone that the graphics aren't as good as Young Justice, and perhaps the plot is more simplistic (then again, we're a mere 13 episodes in as opposed to YJ's 31 and counting), but I can honestly say, I looked forward to Green Lantern each week MUCH more (especially after what, in my opinion, was a poorly handled time skip).
I won't go into detail (that would take paragraphs), but I'll just state that I find the pacing (ESPECIALLY pacing), episode endings, character development and relationships better in GL.
Good graphics are great, but good characters and story are, in my opinion, much more important. Since watching the series for myself, I don't see why people are so worked up about the animation-style; it's actually quite smooth-looking and fits the series itself well.
If you can get past the CGI, this show is really quite a gem. It's not for everyone, but come on, at least give it a chance!