Other factors should be considered in your decision:

1.  Do you have a sugar habit between meals (usually soft drinks)?
2.  Are you brushing and flossing effectively?
3.  Are you a clencher and/or grinder?
4.  Are you following the 'best recommendation' of the dentist,
    or just picking the least expensive?
5.  Are you going to a competent dentist, or just one listed on
    your insurance list?  (these aren't necessarily mutually exclusive
    if you have decent insurance and not an HMO or capitation plan).

JMO,
D