REST肯定是更容易的选择来开发你的应用程序与我肯定会有许多可用的库，为你解决在Android生态系统REST端点。但一个巨大的劣势Magento的REST有，你不能执行它结帐。只能检索秩序已经被放置在系统中不添加订单http://www.magentocommerce.com/api/rest/introduction.html#RESTAPIIntroduction-SalesOrders

REST would definitely be easier option to develop your app with I am sure there will be many libraries available for you to deal with REST endpoints in android ecosystem. But a huge disadvantage magento REST has that you cannot implement a checkout with it. You can only retrieve order which are already placed in the system not add orders http://www.magentocommerce.com/api/rest/introduction.html#RESTAPIIntroduction-SalesOrders

SOAP会有点单调乏味的实现，但它拥有所有你需要搭建Magento的Andr​​oid应用程序的功能。虽然SOAP作为一个协议有它自己的问题。但是，这仍需要进行一些修改到SOAP API，因为有一些错误我已经发现了其中有在Magento要修补的SOAP准确地工作。

SOAP will be a little tedious to implement but it has all the features you would require to build an android app for magento. Though SOAP as a protocol has its own issues. But this still requires some modifications to the SOAP API, as there are some bugs I had discovered which had to be patched in magento for the SOAP to accurately work.

如果您开发的Magento的REST API协议的应用程序有很多因素要照顾。特别是在为Magento的购物车价格规则，目录价格规则，定制的送货方式，自定义付款方式，符合市场预期，除非你让你的应用程序正确地处理这个Magento的这些方面是行不通的问候。

If you develop the app for magento in REST API protocol there are a lot of considerations to be taken care of. Especially in regards for Magento shopping cart price rules, catalog price rules, custom shipping methods, custom payment methods, these aspects of magento won't work as expected unless you make your app handle this correctly.

这是，如果你使用SOAP，因为它实际上是建立在Magento的系统，该系统将按照所有Magento的后端指定的业务规则后端车照顾一些。但是，你很快就会发现，它不是象预期那样，将需要修改SOAP API的某些方面在Magento使您的应用程序可以正确地进行结账。

This is taken care somewhat if you using SOAP as it actually creates a backend cart in the magento system which will follow all the business rules specified in the magento backend. But you will soon find that its not behaving as expected and would need to modify some aspects of SOAP API in magento so that your app can make a checkout correctly.

我知道所有这些信息使应用程序与Magento的API，因为我工作的一种产品，它解决了这个问题 https://crunchcommerce.com/ SDK / 。我们已经建立了其具有的magento桌面的几乎所有的用于移动的功能的SDK。希望我的回答可以帮助你正确的决定。

I know all this information for making apps with magento API because I am working on a product which solves this problem https://crunchcommerce.com/sdk/. We have built an SDK which has almost all the features of magento desktop to be used for mobile. Hope my answer helps you decide correctly.