I bought the Prince Lionheart WeePod and LOVE it! Oh, and Ben loves it too I know it is pricey but I did so much research and this got the best reviews. I also had some gift cards so I only paid for some of it.
We just got it last night and he was able to sit on the big potty all by himself this morning and he even pushed my hands away. It was very comfy for him and he sat on it long enough to fully finish without jumping up too soon (too bad he went #2 as soon as I put the diaper on though). If you have a little boy, the pee shield is great and it is actually tall enough. If you have elongated toilet seats, the adjustable back pegs are perfect and it does NOT slide around at all, it is extremely secure. I haven't done this yet, but apparently the cushion actually comes out so you can clean it if you need to do a deep clean.
I really really love this and just wanted to let you guys know about it since we have so many PTers right now. I would pay full price to have this one again.