Portable Potty

Has anyone tried Evenflo's Potty-to-Go? Chair that folds flat and has a small cup. Or can anyone recommend a good portable potty - preferably one that doesn't have to use special bags or liners? We have the Graco folding potty - it sits on a regular toliet seat but I've found it not stable (as mentioned Toddler bargains too) on public restroom seats which makes my daughter unwilling then to use.

My favorite portable potty is a fold up travel potty that uses 1 gallon ziplock bags! I got it from jeannie's kids club http://store.yahoo.com/kidsstuff/travpotforki.html

It folds up and works great in the car. My daughter loved it!!!

Emily