Metra Tracker built into this app does not provide platform info. In Chicago, at the Ravenswood stop, Metra routinely changes which platform they arrive on without any advance notice on the web. They think an audible announcement is enough since they live in the late 19th century. Sorry, city streets with no crosswalks are hard to cross--even more so with strollers, bikes, wheelchairs. Please put advance platform info on the website. As an example of the neglect of the city around which this rail network is built, the robot announcement says "please look both ways before crossing the tracks." That does not apply to any city stations where you need to use an underpass and cross a busy street.
Other functions: yes, finally, mandated by law and not of their own will Metra now deigns to let you buy tickets on the app linked with the CTA. Please visit Paris or Berlin before you praise this obvious step.
UPDATE: Jan 2016
Now that you have an app, PLEASE INCLUDE THE PLATFORM INFORMATION FOR THE ARRIVING TRAINS. At UP-N Ravenswood, the inbound train at 11am often goes to the opposite side of the tracks. It may seem easy for you on the train, but it is dangerous to cross Lawrence and Ravenswood ave at the last minute. This is the second time Ive written about this. Keep in mind that VERBAL ANNOUNCEMENTS ON THE PLATFORM ARE NOT SUFFICIENT since you hear them only after carrying up a stroller or bike to the archaic East platform.