I have 6 potty chairs and 2 or 3 potty rings in my basement right now. Oh, and a potty ring is still at my mom's house that I purchased for her to have. I have so many because we kept having issues with them! Our very very all time favorite was.....the Baby Bjorn. We have one in pink and one in blue. I liked the ones with the removable bowl (as opposed to the ones that are all one piece). I had to buy them online, none of the stores had them. I did find the Baby Bjorn potty ring (for Mom's house) at Once Upon a Child for $5!!! We liked that a lot, too! So, that's my recommendation. Our others leaked, or tipped over easily, etc. Oh, and I took back the padded seat potty chairs....the twins thought they felt weird. Our fold-up potty rings (purchased to take to Disney on our last trip) tended to fold-up while sitting on them....not so good.
Anyway, for us, the expense of the Bjorn was well worth it!!! Good luck!