I think the poll is a bit flawed. I buy on the iPhone for various reasons but I do most of my research with iTunes on the computer because of it's far superior interface for this. For example, app store reviews are sorted by time only and I can't find out what this other person has reviewed. On iTunes I can do much more research, find out what the most helpful reviews are (they are usually the best in terms of content and accuracy) and also how this person is reviewing other apps. If they are just giving every app 5 stars I may be less likely to trust their views for example. Additionally I can see some related apps in iTunes which I can't see on the App Store. Overall the App Store is good once you've decided what to buy, it's almost useless for research.