I agree with @Diving Dubai
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
single most important thing.
User interface
If you have to read the user manual every time you want to do something stupid like change the time or your nitrox mix, it's a bad design. I don't care if it has every bell and whistle in the world, if it is not intuitive to use, then it's a deal breaker
One word. Ability...
Affordability, Readability. Useability, Serviceability