I have a Sony Xperia XZ1 and the aluminium finish on that is so good. Definitely my nicest feeling phone, though it is still slippery of course. In terms of modern phones I like the textured backs Motorola has been using. Not sure about their long-term durability but they are very grippy and comfortable.
I was thinking more in terms of durability relating to general wear and age rather than short-term drops, scratches, etc. I’ve seen some images of people claiming their Motorola back wore out within months (could be a problem on their end, mine is fine after a year) and we all remember those older plastic devices with the soft touch finish that “melts” after a few years.