It would be nice to have a black and white answer on this but it seems everybody has a very different take on each material.
my take is that Merino is best for sure.. but require a lot more care to look good over time.
Vernasca is a tough leather which require no maintenance care
Sensatec is actually softer but synthetic, if BMW was not telling us it was sensatec I think most people would be fooled by it.
I, personaly believe Vernasca offer best compromise as I think leather will wear better than Sensatec, which I think will degrade and fall apart in long terms 10+ years, like most chemical based textile. And Merino will scratch and look crappy over time as well. So I am going with Vernasca. I have Dakota in my X5 10+ years and it looks great. I have never ever even wipes it
I hope Vernasca will be as good.