Machka and I use Conti Ultra Sports and get good mileage at a good price. That includes lots of centuries, touring and randonnees. We aren't speed demons and while I have some expensive tyres in the cupboard, I am not inclined to use them other than for a fun comparison (and maybe a 24H race).
I've used Gatorskins and I rank them the same as the Ultra Sports for on-road performance. I also have used Vittoria Rubinos and they have lasted well but like the Gatorskins, are pricier than the Ultra Sports.
I think tyres are a personal choice that comes from personal experience.
Incidentally, the above tyres don't have a tread. Not having tread is not an indicator to longevity or expence.