KKās are nice. I tried one for the first time a week ago and they didnāt actually bunch up the string a lot. Unless you have like 5 layers of string, they work really well. I actually really like them now.
Some people are too critical of KK bearings. I wouldnāt call it a gimmick since it does exactly what itās supposed to do (keep the string centered) without losing any real functionality as a bearing. Unless I put many many layers of string in the gap, Iāve never found ābunching upā to be a problem.
With that said, they are completely unnecessary. I would encourage you to learn to keep the string centered on your own; you donāt want to feel handicapped when you use a yoyo with a flat bearing.
Personally, I only use flat bearings on my main throw, but I have no problem putting KKs or Center-Traks on many of my other yoyos in order to tweak itās play just to my liking.
I have a few yoyos w/them. I like the way they play. Most of my yoyos donāt have them. Are they worth the extra$$? Thatās opinion, and I donāt regret buying them.
NOOOOOOOOOOOOOOO! They are so over-rated. Use the stock bearing, or upgrade to a Onedrop 10 ball. KKs cant take the string in the gap a flat bearing can take. Just my opinion though.
I just feel that KK bearings arenāt needed, as concluded unnecessary. Donāt expect much from it, but you can get it for the sake of curiousity, but results vary from person to person. eg. this thread
As you can tell people like them or dislike them. Iād say try one for yourself you make like it, you may not like it but thatās the only way you will ever know.
Personally, every kk I own has came with the yoyo purchased. They play fine for me but Iāve never replaced my other bearings with kkās. Flat bearings play fine as well. Therefore, I play kk and non-kk and never have I found that I play a yoyo because it has a kk. I donāt really think about what bearing is in it.