Re summer tyres - I’m finding the Continentals the best so far. Michelins were very soft and Pirelli PZero were a bit hard. But as MarkMas says, it’s sometimes down to what you can get hold of.
I was initially convinced that Pirelli on an Italian car would be most appropriate, so I changed the worn and wiggly Michelin rears to Pirelli to match the half worn fronts. I backed that decision up with the manual, which says Pirelli or Michelin.
Initially I was pleased but not delighted with the Pirelli decision, then I got a slow puncture in the rear and knackered the side wall, so I took the plunge and bought a full set of Contis. Really pleased so far. Our last MiTo did 40k on Contis and my Defender still has plenty of Continental tread left after 42k miles. The Contis seem to be quieter too.
I reckon a lot of manufacturers’ recommendations come down to politics and whose doing what deal at what time, rather than being specifically designed into the car development process. The Contis are not in the manual, but they are used on the newer QPs