I would not use any software based RAID system. I recomend buying a RAID card from SIIG or Adaptec. That way if something happens to the machine it is installed on all you have to do is throw the hard drives and raid controler into another machine and install the driver and your back online. I have never called SIIG but I can say that adaptec had great costomer service when I called them.
Hope that helps,
I'm being told to use the RAID system in Windows, however I've heard bad reviews. Looking for a little more info and opinions.
I would also avoid using windows based RAID. You are better off with a dedicated card as mentioned in the previous post.
Your budget will also effect which card you go for; cheaper ones are usually software based so it still uses your CPU, but is better than windows one. The Hardware based ones are much better but are usually more expensive.
I would definitely get a RAID controller card if you are using a server.