Re: Precise Pangolin 12.04 LTS or Quantal Quetzal 12.10?
12.04 might be a little more stable because it has been made more conservatively, but unless you are having trouble with 12.10 there is no need to downgrade.
12.04 is supported for 5 years, for businesses using Ubuntu. Individuals usually prefer to stick with the latest release, which is not "beta" but just a little more experimental as it will only be supported for 18 months. The longer support time for LTS is for businesses. You, as a regular user, would not want to stay on 12.04 for five years as everything would be old and crusty by that point.
I hope my advice helps. Please let me know whether it did!