I've heard both good and bad things about this new Thundercats series, I personally think this series is just as good as the 80's version. The designs are nice and the characters are recognizable despite their upgrades.
There are actual elements I'm missing; like the fact that Cheetara play double with both Lion-O and Tygra, and doesn't act like her 80's independent wrestling-woman self. She's really the only element that I'm not entirely satisfied with, she's been changed too much in my taste.
Of course, the majority of the main characters, in this series, are teenagers so it makes for a valid reason to change their characters a bit and I must admit I'm pretty entertained with the sarcastic and proud Tygra.
Now, Snarf doesn't speak in the new series which I'm also able to accept, as his entire role in the old series was that of Lion-O's nursemaid, here he's simply a mascot, at least he makes up for it with charm and doesn't make annoying comments every once in a while. What I'm relieved about is that they hardly changed Panthro's character; he's still the tough mechanic whom I love, though the first few episodes nearly makes the watcher believe they killed him off for good.
Aside from the modern anime-esque design, I wouldn't say Lion-O or Wilykit and Kat are changed much either; Lion-O still shows the naļvete of a child but is also capable of acting seriously on his own, and Kit and Kat are still the little mischievous cubs that all Thundercats-fans loves.
The series is, in my opinion, very convincing for a remake and has a nice storyline to it, despite all the scepticism about it. I think this item was a bliss and I was happy to receive it so quickly. I hope the series will start up again soon, so that the second part of Book 1 will release quicker. :)