What is the difference between paint manufacturers? (Ie. Should I always use the most expensive paint?)

Every paint manufacturer has its strengths and weaknesses.  But just because something costs more doesn’t make it better.  It may just mean the advertising cost for that company is higher.  Each paint must be evaluated in three ways:  1. Appearance 2. Durability 3. Application.  For this reason, we use different paints from different stores for different reasons.