I’ve bad and good things about it. I’m mostly talking about vibe and wobble. I’ve played with one that wobbles and vibes like crazy and one that’s dead smooth, but what are the chances of getting a screwed up one from YYE?
they’re not going to send you a jacked up one. the one you played with that was vibration-eee had probably been thumped :-\
The thing about Yoyojams is, they can be tuned.
If you Lyn vibes, try loosing and tightening it until you can get the vibe to stop. Sometimes you’ll get a bad one that will vibe no matter how you adjust it, a.k.a, my X-ConVict.
All plastic tend to be smoother than bi-metals though. 
~Jump ;D