The common pitfall of applications that use reactive libraries is an accidental memory leaks. Some part of responsibility for that lays on the shoulders of the library's authors, since they often omit the right procedures to release resource in the examples because the library looses a part of its elegance when it is used correctly.
Warp9 is designed with simple idea that you don't have to worry about memory leaks unless you go to the low level and subscribe to reactive variable explicitly (if you do so you should finally remove such subscription to avoid memory leaks).
This simple idea provides you a way to test your code: if it doesn't have explicit subscription then it doesn't have memory leaks of reactive nature. Without similar rule you can't guarantee the absence of leaks, so even small and simple apps can have them. To demonstrate it I've implemented the same app with Knockout, ReactiveCoffee and Warp9.