First, they're apps. This means that I cannot do the normal ebook stuff like change the font size, add bookmarks, or tweet excerpts. While I only care about the first item, other readers will want to do the rest, and I think it would be a better experience if they could. (And yes, you can create this type of content as an actual ebook. You do not actually have to make it an app.)
Update: It turns out that I missed a decision point in Fluid, the review app I was lent. It's fairly early in the book, and that tends to disprove my argument. But it also raises another technical problem with this app; I didn't see that decision point when I read the ebook the 2nd, 3rd, and 4th times. I like to go back and try all the options, but the app won't let me do so. It only lets me restart from after the most recent decision. That's not how I want to use it.
My other issue with these apps is that you don't actually get to make all that many decisions. I hit the 15% mark in
both in the review app I was lent and the one I bought before I was prompted to make a choice. That is far too long of a time. Given that these apps are pitched as being interactive, don't you think the reader should be required to do something more than turn the page?
If we take Coliloquy's decision as a yardstick then over half of the ebooks that I have read are active content. Long before I reach the 15% mark, I have usually made a decision to abandon those books, thus making them as participatory as Coliloquy's works.
I think I understand why it takes so long to reach decision point, and it is likely due to the source content. Rather than create original ebooks, Coliloquy adapted long form fiction. The problem here is that the source usually take a fair amount of text to build up to a major event. That's fine for novel, but not for a format that is supposed to be decision oriented, where the reader is expected to participate.
Flash fiction or fanfic would be better choice than novels. I think just about anything could work, just so long the reader made decisions every 4th or 5th page. If it stretches to much beyond 5 pages and the reader is an observer, not a participant.
You know, I think my familiarity with the original choose your own adventures (still in print) could be affecting my opinion here. Those books weren't written in the traditional sense. Instead they were crafted as decision trees, and the text was added so you would be led from one decision to the next. Other than the decisions, there was no story.
But with Coliloquy's works, it feels like the story was written before the decision points were added. I think that was the wrong approach. If the reader is really supposed to be a participant then shouldn't you start with the participation and work out from there?