It's worth of your time, if you're a fan of shounen manga. Especially it have good OP ED song.
I tend to watch anime over reading shounen manga. It's giving different feeling as it's being animated especially in battle scene.
I watched it back when it first released and liked it.
The spin-off thing didn't really look like my thing, but the original is definately a fun action/shounen show if you're into that.