Incredibly slow
This app is so unbelievably slow on my iPhone 3G iOS4.2.1. It takes like a full 2 seconds between when I type a single symbol and when it shows up.
Also, this app simply connects you to the wolfram server, so you still need an internet connection. Considering this, $5 is a bit much when you can just use their website for free.
Rteub about
Wolfram Multivariable Calculus Course Assistant