With nice cel-shaded graphics and fantastic CGI in a nice blend, Appleseed will not disappoint the eye. There is enormous attention to detail, reflections, shading and other small things. Many of the scenes, especially involving the giant city complex, could have worked as art if you froze the frame.
The story is pretty unoriginal though, which is a shame. I won't tell you anything, but it's likely you'll see references from a wild collection of sources. Characters have varying depth, and some felt like they needed a bit of fleshing out. Lip-sync was so-so and the same goes for most of the voices(in Japanese).
Music is cool and futuristic, with a few surprises thrown in(Basement Jaxx? What the?) and fits the scenes nicely. Sound follows the same pedantic attention-to-detail pattern as the animations. The action is very, very cool, even though it's not a pure action fest.
While the storyline doesn't feel too much like Manga, the animation really is. Manga eyes can be bugging, but it was OK. The transformer-esquire mechs where really cool even though they were very similar(then again, I've never watched Transformers).
So, in closing, is this worthwhile? Sure. It's storyline is not so complex you need to scratch your head, like other anime(Akira or Final Fantasy), and the animation is a feast to the eyes. Give it a try.