*If you don't want to read everything I wrote, then just skip to the last section. That's what's most important.
Rurouni Kenshin is a brilliant classic that will appeal to all types of audiences. It is well thought out, a perfect length, with interesting multi-dimensional characters.
Plot
This manga starts out taking place during the tenth year of the Meiji era (during the 1800s), when the carrying of swords just became illegal and the art of the samurai is on the decline. It is about an exceptionally skilled samurai who fought as war assassin for several years before suddenly, without warning, disappearing. The manga begins with the meeting of a young dojo master (Kaoru) and this mysterious wanderer (Kenshin) who has sworn never to kill again (ooo, I wonder who he could possibly be). They become friends and face many challenges together, along with the friends they pick up along the way.
Characters
The main characters are interesting and all very likable.
Kenshin: Appearance: Very kind, a little dumb, funny. Reality: Very intelligent and highly skilled, but still kind. He's the sort of character who is just plain good. He uses his powers (extreme skill, unbeatableness) for good and not evil
Kaoru: The female lead. She's been one of my all-time favorite characters for a long time, because she's so simple. By simple, I do not in any way mean stupid. She is actually very smart, and knows swordsmanship well. By simple, I mean that she always expresses how she feels. Whether she's happy, angry, jealous, frustrated, whatever, everyone knows it. Also, she's a horrible cook, which is an ongoing gag in this series, as she gets really angry when people insult her cooking.
Yahiko: Kaoru's student.Very stubborn and often argues with Kaoru.
Sanosuke: A fighter for hire who becomes friends with Kenshin and Kaoru. He's kind of your classic shounen male lead. He's strong (but not nearly as strong as Kenshin) and tough (way tougher than Kenshin) and a basic element to the story.
Megumi: A doctor who becomes friends with Kenshin, Kaoru, etc. She has a thing for Kenshin, but they don't make it into a big deal in the manga. She's your classic, beautiful/graceful japanese woman. However, she really likes to get on Kaoru's nerves, because she knows Kaoru is jealous of her cooking skills and elegancy etc.
The author spends a nice amount of time developing each of the characters, as they all are strong and want to help Kenshin in their own way. Sanosuke, especially, is often seen fighting alongside Kenshin.
Art
Starts out pretty good for a shounen manga. Gets to be really good. Then goes down a little bit, but stays really good. If I were to grade it out of ten, I'd say: 8, 10, 9.
Appeal
Here's why this manga will appeal to everyone.
It has all the basic elements. Comedy (which everyone likes), romance (between the two leads, and no, that is not a spoiler at all), history, really intricate battles with well-thought out techniques, and a journey. By this I mean, the characters are trying to reach a goal, not just loafing around aimlessly.
None of the characters are annoying, or a major liability.
The plot twists. The first arc is pretty straightforward, and is basically what you'd expect it to be. However it is done very well, so that it feels like a classic, rather than a copy of a classic. Then comes the second arc, and it throws you head over heals. Trust me, no one expected what the second arc brought. Surprise after surprise after surprise, and twists you never would have seen coming. It is very nice in contrast to the first arc, because between the two, all the basic elements that you could hope for in a story are covered.
Satisfying ending. Maybe you won't love it, maybe it won't be the best ending ever for you, but you'll be satisfied with it. You don't feel let down by the way this one ends.
The fights never get repetitive. Even for someone like me, who isn't all that into battles, the fights in Rurouni Kenshin were interesting. That's because there were always new techniques that were being used and you honestly couldn't tell how a battle would end up. And it wasn't just for the protagonist. His enemies always had new techniques as well. So the fights were very capable of captivating your interest, no matter who you were.
So check it out. It isn't the most profound manga in the world, but it is a classic, and it just makes you feel good to read it. And sure it's a little older, but in my opinion, it easily outweighs some of those most popular shounens of today, such as Naruto and Bleach.
By the way if you can, I would suggest reading it in volume form. It's just better that way.