[Darkblade48]

I doubt that a yeast mixture lasted 2 months, unless you had a very large batch of sugar water and used the tiniest bit of yeast to start off the colony. Mixtures that last more than 3 weeks already sound too good to be true (especially if people claim they had strong/consistent CO2 during the entire time).

In the end, you will realize that pressurized CO2 is much cheaper in the long run, and saves you the hassle of mixing up new sugar batches on a regular basis. In addition, pressurized is really the only way to go for larger tanks.