Years ago where I worked, we had one individual in our group, "Glen", who dressed the same every day. White short-sleeve shirt, pocket protector and black pants. Think Dilbert in real life. 5 days a week. I am not exageratting. Halloween rolled around one year and it was on a Friday. We talked amongst our group and got the vast majority of the people in our section of the office, 30 or so, to dress as close to him as possible. The day rolled around, we were sitting in one cube area talking early in the day when "Glen" walked around the corner. He sat down on a the edge of a little table. We just continued with our converstaion. He took a look around at everybody, smiled and said "You guys are looking pretty sharp today!".

My experience with iOS, RIM and Android devices indicates, yes you will need to test on the devices. Example - We recently changed our app for RIM to be compatible with several new devices. I made changes to the screen layouts so that all looked pretty in the simulators. When we installed and tested on the devices, text and images landed in different places on the screen. We went back made changes and they looked like crap in the simulators. Installed on the devices and TaDa! They looked great. Go figure. We also stumbled upon an error in the RIM OS that doesn't show up in the simulator for a particular device. It is only shows up on the actual device itself. So the moral of my story here is: Test on the device you say you are compatible with.