You have two ways to go about this: Watch the original anime series and be blown away by the majesty of Rurouni Kenshin: Tsuiokuhen or watch it first and then the original series and be disappointed by how it can't compare. Granted that I've never watched the anime (But read the manga), but how could it compare to this?
The story is about how Kenshin got his cross-shaped scar but it's so much more than that. It displays the violence of such an era and the dangers of choosing sides with a sword, but also that of a love story. The love story aspect shows a more emotional and human side to the killing and the ideals behind them. The blend of romance and violence in such an era is masterfully played and is simply stunning to watch as it unfolds.
In terms of characters, Kenshin and Tomoe stand out the most as the two mains. It's about them and everybody else works around them and with them, all for the better. You see Kenshin grow and change, and how Tomoe changes around him as well. They develope and one can simply wish that it would go on longer but the length of the OVA stops that. But even with the short length, they can feel more real than characters in longer series.
Tsuiokuhen has no qualms with showing plenty of blood with it's violence, and it only heightens the kind of era that had come to pass. The stark realism of the time is accompanied by some beautiful scenery; the background and the surroundings look absolutely gorgeous, which is saying something considering how old it is. the only thing that prevents it from being perfect is some out of place live action shots. They rudely interrupt the flow but the rest of the animation will soon draw you back in.
An anime this good looking must be met with sound just as good, but the sound, dare I say, exceeds the animation. The music is unbelievable. It works perfectly with the era, with the events playing out, with the battles fought, with everything. It can be subtle but sometimes a quiet tune sets the mood just right, or a more upbeat ditty to get the blood pumping for a fight. The music works, simple as that. For VO, I spent a minute in dub and switched to sub. The only blemish in sound is the dub, which feels flat and emotionless. But considering that I watched it all in sub and only a minute in dub, I'll simply count the sub towards the score. In the sub, the characters sound right; you can hear the emotion in their voices as they breathe more life into the characters instead of leaving them as lifeless husks of humans in the dub.
If you've got this far, then you know how much I love this series. At what it does, what it dabbles in, it's one of the best in. This is simply a masterpiece and you owe it to yourself to take a break in whatever you're watching to check this out. It's renowned for a great number of reasons. It's one thing to hear it secondhand, but another to witness it for yourself.
Rurouni Kenshin: Tsuiokuhen