GreenShadow It’s still a 100%, and it’s still Metagross, so it’s still a powerful Pokemon (I am very jealous!). So while I would umm and ahh about it, I probably would evolve due to it being such a good Pokemon, even without Meteor Mash.
If you have a lot of Beldum candies, or even lots of spare rare candies, I’d say it’s probably worth it to evolve and power up 