I just went through a Quisition deck on my iPhone and it worked great.
One of my goals has always been to have flashcards on the go and Quisition on the iPhone gives me that, without any modification to Quisition needed.
If the iPhone had a custom SDK, it would have taken me weeks (or even months) to port Quisition. It may have been slicker, but you can't beat something just working, with no additional effort required. And a certain amount of slickness can always be added later via an alternative stylesheet triggered by user agent.