I myself didn't have any problems with spending six hours on the same problem, but what I did deal with was waiting 40 seconds for another problem to load. Then I spent about 20-30 seconds on it. Then I waited another 40 seconds. You see the problem here. In addition, for each topic, at least in Geo/Trig, Aleks had somewhere around 3 different problems. If you were going through the infinite review, and there were only two topics in there, you would see the same problem every 4-6 problems. That is not good. There needs to be variety.