There are quite a few reviews rating this app low, justifiably, due to its lack of service and affinity to crashing, particularly on devices older than an iPhone 5s.
I experience no such crashes on 5s, iOS 9, and enjoy having less to carry, but do have two complaints.
1) The app, on long lectures, likes to automatically sign-out—presumably for security and/or academic honesty purposes. The app should be designed such that it remains signed in for, at least, two hours of inactivity, if not indefinitely—which leads into the next point.
2) While it is reasonable to have to input the session ID each time, since that changes per session, it is particularly annoying to have to input all the login account details for every session. A "Remember login details" or "Keep signed in" option should be present, to allow for smoother access.
To anyone thinking of using this app as an alternative to TurningTechnologies clickers, either make sure that you wont be doing any quizzes or tests with them, or just hold off for now. The tried and true approach is more attractive at this point.
UMCP Undergrad about PointSolutions, v2.2.1