according to consumer reports the price diff is $65 a 100 sq ft, vs 45.
the more expensive ones are rated about 7 out of 10, the cheaper ones
are 59 out of 100

most people move after 7-8 years and any shingle will look ok after
that long, so if that's the likely outcome in your life, most buyers
will not give a darn about the higher-priced shingles.

if you're willing to live with 3-tab shingles, the "CertainTeed XT 25"
only cost $35 and are rated a little higher than the CertainTeed
Landmark 50. the XT 25's are rated higher on weathering and impact
resistance than the Landmark 50's.

so actually by going with the "CertainTeed Landmark 50" model, you'd be
paying almost twice as much as the XT 25's and getting a product that
does not last as well.