~Some minor spoilers, but nothing super revealing~
I am not a fan of racing. Things like Nascar bore me to death. I find it to be one of the worst video game ideas. And, when it comes to anime, even things like Initial D and Speed Racer aren't able to jump start my interest in racing. When I first got the intention of watching Redline, I hadn't a clue it was about racing. I was actually watching a conversation where people were discussing the animation on an anime forum and I decided that all the positive things they were saying about it was an excellent reason to watch it.
Again, I hate racing, so you should take me seriously when I say that I find Redline to be a masterpiece. A futuristic race involving people across numerous alien species taking place on a hostile planet? From that concept alone, one would probably think of the Pod Races in Star Wars. But, trust me when I say that Redline is actually far better than that mediocrity.
As I initially said, it was the discussion of Redline's animation that drew me to watch it, and I was far from being disappointed. Redline exhibited some of the best visuals I've ever seen from an anime. Never before have I seen an anime I felt could be comparable to the Kara no Kyoukai series (which I've felt has been a pinnacle of animation for a very long time) in terms of animation, if it didn't outright blow it away. The very opening scene of this anime where it has the nut shells hitting the floor set the entire stage for the animation quality; showing amazing quality and details that few animes have ever actually put the time and effort into showing.
The sound is perfect. I know that it seems like it'd be difficult to screw up the sound on an anime, but Redline put almost every anime to shame when it comes to sound. Perfect voice acting, perfect soundtrack and perfect sound effects; just an overall perfect performance from the sound.
Often times when watching anime, I have this complaint that the characters aren't real. That they don't seem like a realistic archetype of what humans actually are, which is typically followed by not making very realistic choices, which then end up placing the characters into a flop of a plot because of their terrible choices. The characters in Redline are beyond believable, but their personalities and background information help you better understand them as a person. I can claim that I've known many people in my life who would do the same choices and paths as the main protagonist, JP. Although, romance seems to spark up a tad easily between him and a special girl I'm not revealing the name of, it's still fairly acceptable, for it does nothing to break the plot and helps you understand the characters even better. This is one of the few instances of perfection out of characters I have ever seen come out of animation.
The story of Redline is fairly simplistic at it's core. JP is in the biggest race in history, but his buddy is constantly selling him out to lose for the mafia for tons of money, so JP has to learn how to outdo racers with weapons and his buddy selling him out. But, on top of this, they're racing on a planet that's filled with a hostile race that doesn't want their military compounds being filmed for the universe to see and uses military and doomsday-like weapons as a means to bring down the racers. To top it all off, the people in charge of and racing in the race (called 'Redline,' so you know) are all even more pumped into racing with these added hostile odds, which all leads to huge, dramatic scenes of clusterfucks of weaponry and destruction. The plot is fairly solid, despite being filled with clusterfucks of weaponry and destruction.
As I said in the beginning, Redline is a masterpiece. Granted, I didn't give it a 10/10, but that's because of how critical I am on racing based plots. I was entertained 100% of the time, and to be honest, what more do you need from an anime?