I need to get a 6tb drive to do post production on my documentary on FCP7. This will entail a lot of editing and rendering. I normally use G-tech. That said, the Western Digital 6tb drives are around 200 bucks cheaper. I'm thinking of this: Western Digital 6TB My Book Studio Edition II Quad WDH2Q60000N (http://www.bhphotovideo.com/bnh/controller/home?O=&sku=757710&is=REG&Q=&A=details)

Is using this a bad idea? Will I be much happier if I just pony up the extra money or can I use this one and save the dough?

If your system will handle them, imo a few smaller HDs in a Raid config. are faster and safer for back up. Make sure you have good air circulation around them.

If you have everything on one HD and it stops for some reason ...??

Cheers.