Anyway,that i have to say is that there is not a best tyre,sometimes a make has a advantage sometimes have disadvantage.
Dont believe whatever you hear,specially from drivers that they dont had a good rally or plenty of bad results.
Its very easy to blame the tyre,while the problem could be a combo from different reasons,or even the driver.
Pirelli are very good at motorsport tyres,specially at rallies,the sport we love.Of course sometimes Michelin have/had a better tyre,but that isnt forever.
Tyre makers make ''evos'' of tyres,that they dont give to public the info at all,and you cant find it with a mark at the tyre(thay can recognise of course),everything is the same.But when you drive the tyre is different.Only from inside info is possible to know some details.So that today Pirelli is better,maybe this will change with next evolution of michelin,or maybe not change.