In my views
1. No viruses
3. Pretty Cases
4. No activation or serial numbers to deal with
1. Inconsistent. (Does not really crash or freeze, but I fear there is a ghost in the machine)
2. Ridiculously over priced.
3. Limited Hardware Support/Availability.
4. Lack of retail software availability.
5. No backwards compatibility. (Old apps/hardware wont work when you upgrade operating system)
6. No support. (Average support suggestions include "You just gotta find a workaround")
7. Closed Market (If you want an Apple, you have to buy an Apple.)
(No competition to lower prices, increase support, or advance hardware/software)