The "recommended" hardware for Pleco (iPhone 3GS) is considerably more advanced than most of the other smartphones available in China - performance-wise, it basically beats everything running Windows Mobile and all but the most expensive / high-end Android phones. Just because the cheaper iPhone 3G isn't the top recommendation on our hardware page doesn't mean it isn't a good phone, though - I use one myself, in part as an incentive to keep Pleco running smoothly on older phones. To be honest, that hardware page is mainly tailored towards Americans (still the majority of our customers), who are paying $100 for an iPhone 3G with a contract versus $200 for a 3GS, and for them I think it's an easy decision to go with the 3GS.
Another option would be to get an iPod Touch - those are considerably cheaper than iPhones, they're available service-contract-free in the US for $200 and the importers can't add that much of a premium on top of that since there are so many of them out there. And they're extremely thin and portable, so you could feasibly carry both an iPod Touch for running apps and a super-durable, keyboard-centric BlackBerry or Nokia phone for phone calls / text messaging / email.
A lot of the inexpensive Chinese smartphones either a) run a proprietary / Windows-CE-based OS that isn't going to be very good for running apps in general, or b) run some variety of Android, but due to their low cost are unlikely to keep being updated for the latest Android versions - the manufacturer can't afford to re-adapt their phone's software for every new version of Android. So it's unlikely most of those low-end Chinese phones will see a steady stream of OS updates like the high-end HTC phones (which, as I said, cost as much as iPhone 3GSes) do - many of them will be running an obsolete operating system from the day you buy them.
