As a consumer, I hate QR codes. They totally obfuscate what is going to happen -- Many times there is little to no information about where a QR code will send me. As an iPhone user, I also need to download an app to read the QR codes, and suddenly I now have another choice to make -- which app is the best quality and least spammy of the ones listed. As a designer, I also think they are quite ugly -- Try putting one o…
Yes, I do realize there are QR Code "hacks" where the codes are colored and/or integrated with logos, etc to look less ugly and those hacks do look good (or at least less bad) on a web page, but they destroy usability of the codes in the real world (by removing data redundancy, killing the contrast to the point where devices with cameras with low dynamic range won't scan it well, etc).
I don't mind so much the other issues, I like that they can be used flexibly for just about anything from encoding a url for marketing to doing internal inventory management.