Has anyone used their new variables stuff? The whole custom variables thing was ludicrously complex. Google's competitors just let you supply a JSON object with each event so you could add whatever you wanted. Google also bafflingly would only show the average value of numeric variables which is beyond useless.
Hopefully they also fixed the major problem with their previous analytics library which was that it only supported one reporting id at a time. (Under the hood it would correctly work with multiples but the API ensured a singleton for the top level "tracker" which then forced only one id.) This causes problems if you have multiple libraries or components who want to do their own reporting.
As announced at Google I/O, app tracking is now a first-class citizen in Google Analytics. The old SDKs used web tracking concepts, but now anybody can use the new SDKs and the new reports, which are designed just for mobile apps.
To answer your questions, the new App Analytics SDKs (Android and iOS) support multiple reporting IDs. The new custom variables are essentially named dimensions and metrics that can persist for the duration of a session, and are much simpler to work with than the custom variables in the old SDKs.
Hopefully they also fixed the major problem with their previous analytics library which was that it only supported one reporting id at a time. (Under the hood it would correctly work with multiples but the API ensured a singleton for the top level "tracker" which then forced only one id.) This causes problems if you have multiple libraries or components who want to do their own reporting.
The previous mobile libraries were very much the minimal work to pretend they worked like web sites, which really doesn't work well. I wrote about this at http://blog.appington.com/2012/08/13/technical-differences-m...