Specifically, if we take the example of iPhone 5, following is what goes for and against it:
For:
1. Good design
2. Large App ecosystem
3. Polished, clean UI of IOS
4. Ease of use
5.very light weight
Against:
1. Tightly coupled with iTunes
2. No USB mass storage
3.poor quality of materials (scratches, paint coming off, etc.whole bunch of complaints)
4. Does not gain signal when moving from low coverage to high coverage area (iOS bug)
5.can't transfer files, photos via bluetooth
6.exorbitantly priced
7.sub-par camera (purple haze, lens flare complaints from users)
8. Maps software is way behind Google maps
9. No compliance with standards - Lightning cables are expensive and not freely available at a local shop in case one cable malfunctions or breaks.
10. Too little too late - there are more advanced features in Samsung Galaxy S3 which was released about 5 months earlier than iPhone5 and still the iPhone5 costs more and does not match up with the features offered by SGS3.
YET, people buy an iPhone 5 after paying a hefty premium. It just defies any sense and logic.