I know plenty of people here are fans of the excellent Chunky Comic Reader (http://chunkyreader.com) for iPad. The developer's just put out a call for testers for Chunky NG (for iPad AND iPhone). If you're on Twitter, bung him a DM (https://twitter.com/ChunkyReader/status/989793025919537152) for a TestFlight invite and give him some encouragement and constructive feedback. (If you're not on Twitter, you can email him via the website linked to above.)