Don't listen to what common sense media has to say about it, this is a great show, one of my favorite cartoons ever!
This was my favorite show growing up, and recently I've decided to rewatch the series. It's even better that I remembered! It's great for all ages, and has something for everyone!
First of all the stories are outstanding. I mean sure there's a few kind of silly/random episodes, but that happens with every series. All of the stories seem to weave together and actually make sense and are engaging and exciting.
The animation is top notch, especially the action scenes!!! As someone who plans on majoring in animation, I can tell you it blows me away! The animators are very creative with their camera angles and the action scenes in particular are very well done.
Now about the violence, I can understand where some of these parents are coming from when they're freaking out and complaining that it's too violent; I almost felt the same way myself when I started watching this again. However, then I thought back on when I watched this show as a kid (I was about 6 or 7 when I first saw it), and the violence didn't bother me at all then. And that's saying something, because when I was that age I was scared of everything and couldn't even sleep in my own bed, however I wasn't afraid at all of this show and the violence didn't bother me in the least. I honestly think that stuff like that just goes over kids' heads (they're probably used to it, knowing how violent kids' movies and shows are these days), so parents, you have nothing to worry about.
I personally think that the amount of violence is perfect; It's violent enough to put older kids and adults on the edge of their seats, but not too violent that it's not watchable for little kids (Like I said, it just goes over their heads).
And the show isn't all action either. It's got some great humor (It's hilarious even if you're an older kid or adult, but it also has stuff that the little ones will find funny too), and most importantly, incredible character building.
In fact, for me, the characters are what makes the show so awesome! They're very believable and not as cold/lacking personality as a lot of the characters in superhero/comic book cartoons are. The character development is brilliant, you definitely feel like you get to know the characters better and better as the series progresses. The turtles and Splinter all have a great relationship as a family, which is really the core of the show. There are some great messages here, for both young and old.
Shredder too, is a very exciting character. Unlike many villains of other cartoons, who are often bumbling or easily defeated, Shredder is a force to be reckoned with!
And it's not just the turtles and Shredder who get great character development, but also less frequent characters like April, Casey, Baxter Stockman, and Nano just to name a few.
Overall, excellent series, I highly recommend it!!! Wonderful stories, animation, action, humor, and characters! If you're not watching this, you're definitely missing out!