i deal day in day out with lease hire companies. most calculate the cost per tyre against expected mileage to gain the most cost effective tyre. known as ppk accounts (pence per kilometer)
majority have a contract to use michelin.
they will give you the best mileage, be reasonably quiet, grip well in all
conditions and have the latest up to date technologies.
but as jasons says you will get very many different views on what is best.
just wait for the "my car went from michelin to nankang/fulda/maxxis/toyo/ etc and it gripped so much better"
you are comparing a worn out tyre to a new tyre, that is no comparison. an old tyre with around 2mm (or a lot less in most cases i see) just doesn't generate the tread block movement and thus heat to generate grip. that's why they feel better.
at the end of the day it's your money.
but ask yourself this question.
if the usual "just as good" tyres are
actually just as good, then why don't the manufacturers fit them from new??? think about how many new cars they sell, then multiply that by the savings on a set of tyres and work out how much they could save each year by fittings these other "better, cheaper" tyres
the fact that they don't tells it's own story
you pays your money you takes your choice