I looked into this a bit but never mentioned it because of cost and time. The other option besides TapaTalk (and the security concerns that MaxBurn mentioned) is for me to purchase a license for the
vbulletin mobile platform which supports iPhone and Android phones. The problems are that, one, it's costly, two I would need to develop the app based on our forum which means I'd need to either have a Mac, or a contrived VM version running their OS in order to get an iPhone variant created (android I could do right now), three, it's still somewhat immature and problematic in some cases. I've been using it for the AVSForums app and it does work fairly well on iOS. I have had no exposure to the Android version though, so I can't comment there.
If people felt it would be worthwhile enough to explore, maybe it could be a group-purchased solution?