I can't even get it to work between a Kobo Touch and an iPhone. But I see no reason why it shouldn't work between iPhone and iPad, considering you could easily have the Kobo apps and no Kobo eReader, or a smartphone and a desktop computer, for example. If it's "cloud syncing" why would you need an eReader or a computer to sync?
that you can synchronize between devices. Right on the iTunes store in the app listing, and here
on the Kobo website, and I'm sure in other spots too.
[…]even your bookmarks follow you so you'll never lose your place.
I received another response to my ticket today. They tested the two books I tested (one free and one paid kepub from the Kobo store) and here's what they had to say.
We have looked into this issue and we have determined that there is an issue with these two eBooks rather than the Kobo app for iPhone/iPad. These eBooks do not bookmark properly. We apologize for the inconvenience this has caused.
So I asked them to tell me a free eBook on the Kobo store that DOES work.