I got mondo for 99 cents, and was sorely disappointed. It's slow, clunky and the controls are horrible. Sometimes you can't select all the cards. I can't figure out how to move an entire pile of cards in Spider. Took me a few tries to finally get the clipping thing, but that doesn't move the entire pile.
The fact that I can't figure it out, tells you a whole lot about the game's suckiness.
I'm so glad I didn't waste $9.99 on it. I still feel like I wasted money on it, and it was only $0.99!
I vote for Solitaire City (the lite version is great, I'm contemplating buying the deluxe version. The controls and animations in this one is the best of the bunch) and Solebon (Sol Free is great, and the controls are clear and easy, but it's sometimes hard to select a specific card in a pile to move a partial pile, and there's no landscape mode (I think, at least there aren't any in Sol Free)).