I dont care what you do but there is more then a 1% chance that some problem or another will derail what your doing regardless of what device, platform or toolkit you use. The probability Apple doesnt accept your app on grounds unrelated to unity or unreal is way higher then 1%. For all you know apple wont be accepting indie app store submissions at all by the time your done. Thats why it would be nice if phones were treated like normal computers opposed to walled gardens dictated by a single entity.