This Dual SIM - smartphone works almost as good as the iPhone 4 in most respects - but it will cost only a quarter. The display is a little darker and a trace coarser resolution, the reaction rate only just noticeable but not annoying slow. The battery life is under normal usage against 48h - so something like the iPhone 4. The camera is at best minimally worse than the iPhone 4, only the 4S makes visible sharper images. Video I have not tested. The feel, especially the back, of course, falls in comparison to Apple from clear.
Conclusion: A good and very cheap, visually similar alternative to the iPhone 4, as opposed to this but with dual SIM and the benefits of something more open app market and the somewhat freer configurability. I can not say anything about the long-term durability.
