I'm both an iOS developer, and a low-vision user, so the subject of accessible transit apps is important to me.
There's so much natural overlap between the transit riding population and those who benefit from accessible apps. For that reason, I wish more transit app developers would think more closely about accessibility when they make these apps.
I haven't tried every transit app that works with the OC Transpo data, but of those I've tried, many will use text sizes that are too small or colour choices that lack sufficient contrast. Case in point, the official OC Transpo app shows all bus arrival times in the smallest text size used anywhere in the app, and in some cases using cyan text on white background.
I don't use a screen reader day to day, but know how to test it out after making some of my own apps VoiceOver compatible. Although I'm not part of the actual target user population for VoiceOver, I'd say based on my testing that all the apps I tried had a ways to go before they'd be nice to use for a blind user.
On a related note, if anyone wanted some more specific feedback on how a particular transit app works (or doesn't) for low-vision users, I'd be happy to take a look and provide feedback.