Well, being that Kenshin is my VERY favorite anime, I should answer your questions!
Rurouni Kenshin is a fantastic anime that became my favorite almost instantly. It has everything: Comedy, drama, romance, action, history...It's a fantastic anime!
It starts with the Rurouni arc, which is the lighter, funnier portion of the show. Kenshin is introduced as a harmless rurouni (wanderer) who has been wandering around Japan for the past 10 years. He is kind, humble, and very polite, yet he has a dark past. We find out that this "rurouni" was once a hitokiri, or assassin, who fought during the Bakumatsu of the Meiji Restoration. Kenshin is a clumsy, friendly person, but when he must fight, he does so with the elegant and very fast Hiten-Mitsurugi Ryu, along with his sakabatou, or reverse-blade sword (this enables him to attack without killing anyone). He's an amazingly skilled swordsman who hides behind his rurouni self in an attempt to keep himself from killing anymore. The rurouni arc is a good start for Kenshin, however, it does have a lot of filler episodes and some sillier situations. There's less blood, although violence
is present throuought the series. Since it's set in this particular era in time, the absence of violence would seem unrealistic, to say the least. The story progresses into the second arc, or the Kyoto Arc, which is the real meat of the Kenshin anime.
The Kyoto Arc is much more violent and bloodier than the Rurouni Arc; however, it's ten times better! I'll put it in spoiler brackets, since it's kind of hard to not spoil it when describing.
[spoiler]The Kyoto Arc is based around the scenario in which Kenshin must travel alone to Kyoto to fight the hitokiri, Shishio Makoto, and keep him from his devious plans to take over Japan. While this arc is a lot more violent than the previous arc, all of the killing is done by Shishio's men, the Juppon-Gatana, or by Shishio himself. Kenshin (nor any of the other "good-guys") kill anyone. Also, in the Kyoto Arc, the character Anji makes his appearance. Anji is a fallen Bhuddist priest, which is the one weak point of the Kyoto Arc, especially in the anime. In the end of Anji's story, it kind of glorifies Buddha, although this doesn't happen to such an extent in the manga. It's really not too problematic; however, since Anji only appears as a major character 3 or 4 times. This one bump in an otherwise smooth series is not much to worry about, it's not enough to make it not worth the watch. n.n[/spoiler]
As far as the third arc in the anime is concerned, I'll have to let someone else explain it. <<^_^; I have yet to pick that one up, since it's completely filler episodes, and I hear it's not as good as the other two arcs. I'll have to pick this one up from Netflix...XD
Anyways, I highly reccomend this series, and I think you should definitely give it a try! It's very clean, the language isn't too too bad, and there is no sex whatsoever. One of the Juppon-Gatana, Yumi, does have a very low kimono, and another character, Kamatari (also from the Kyoto Arc), is meant to be a homosexual. It's completely one-sided; however, and is meant more for comedic relief. Also, since Kamatari is one of the antagonists, all of the main characters look down upon him/her and his/her lifestyle. Other than those two, everything's great! n.n
Anyways, hope this little "clarification review" helped you out, and I hope you end up watching this series! It's definitely one you shouldn't miss!