Actually, there are quite a lot of standard UIKit objects used in the iPhone version, so it definitely isn't written from scratch. Granted, it doesn't explain why the Android version makes such a poor showing, since I'm pretty sure Android has equivalents for a lot of those elements.
There are, however, so many possible reasons why Android versions get the shaft that it's nearly impossible to say why any given pair of apps are so different in quality. It could be that it's easier to find iOS devs that really care about UX and polish (lots of self-selection going on here, similar to Mac/Windows third-party devs). It could be that a company asks their iOS dev to knock out an Android version, when they're not competent at developing for the platform. It could be that the folks in charge of getting mobile apps made for their company just like iPhones more (not a stretch, given demographic differences) or see them as more hip or marketable and funnel more money that way. Or, it could be that, after spending lavish amounts of money on the iPhone app and seeing it not set the world on fire, they scale back to merely "establishing a presence" on Android instead of making the same effort.
A lot of these behaviors wouldn't surprise me, particularly from companies whose primary business is not creating software.
There are, however, so many possible reasons why Android versions get the shaft that it's nearly impossible to say why any given pair of apps are so different in quality. It could be that it's easier to find iOS devs that really care about UX and polish (lots of self-selection going on here, similar to Mac/Windows third-party devs). It could be that a company asks their iOS dev to knock out an Android version, when they're not competent at developing for the platform. It could be that the folks in charge of getting mobile apps made for their company just like iPhones more (not a stretch, given demographic differences) or see them as more hip or marketable and funnel more money that way. Or, it could be that, after spending lavish amounts of money on the iPhone app and seeing it not set the world on fire, they scale back to merely "establishing a presence" on Android instead of making the same effort.
A lot of these behaviors wouldn't surprise me, particularly from companies whose primary business is not creating software.