Probably here. (and you can probably tell by the abundance of postings recently how much time I've had to spend on it lately... )
Basically, iXForms in its present form works adequately from a user/functional perspective (although its missing such things a itext and repeat groups), but is a horrific mess! Its Objective-C, using a really good but slowly sunsetting UI library (XLForm) on top of a bunch of custom middleware (ARC) sitting on top of an bunch of arguably beta+ (non-ARC!) low-level XForms handling code, all sitting on top of an fmdb wrapper around an SQLite database. Again, it works, but .... OMG I'd never show my mother!
I'm in the process of rewriting it in Swift using Eureka for the form UI and Realm for the DB layer, which will significantly diminish the code bloat and make it feasible for someone other than me to understand what the heck is going on. Soon as I have a minimally working (eg simple text-only question form) running I'll put it on github and let others watch - and contribute - to the other features being re-added.
But it isnt, and likely never will be, a strict port of ODK Collect to iOS. Rather, its an iOS XForms client attempting to be compatible with ODK forms, OpenRosa API, Central REST API, javaRosa behavior (eg support same XPath function suite), etc. [hence my earlier comment: "do people want an iOS ODK Collect app vs a native iOS XForms-compatible app?"]