Review ratings

I'm trying to come up with a more practical rating system:

• Tier 1: World Changer - buy it if you can (e.g. digital cameras vs film)
• Tier 2: Upgrade - you'd consider getting this even if your current product was still working
• Tier 3: Decent - you'd get this if you were looking for this kind of product, but not something you'd make sacrifices for
• Tier 4: Special Consideration - you'd only get this if you needed some of the features that no other product had, or you really liked the brand or design
• Tier 5: Avoid