They might have a little vibe, that’s called YYJ vibe. The plastic they use could be a little inconsistent and cause a vibe. It happens to every 1 of 20 YYJs or so.
Not sure what your budget is but If you can, get a Liopleurodon, it was the smoothest yoyo I ever threw. No vibe, or wobble unless you had a really bad through. As for grinds, it can grind all day. It is “candy blasted” whatever that means. When you slide your finger across it you will know what I am talking about. It feels soft, and slick at the same time. It really is an amazing yoyo. I have not thrown any other I Love YoYos but their other yoyos may play the same also.
A raw yoyo like the eneme is terrible for grinding.
The Liopleuridon is an awesome yoyo and will grind well but if you have wimpy fingers it will pop one off in a hurry! lol Its just real heavy.
I would have to say the new 5150’s and the blasted wedgie’s are awesome. Problem is there are so many good grindable yoyo’s out there that its really hard to decide. If I were you I’d just find a metal that is bead or candy blasted and go with what you think looks cool. You won’t be dissapointed.