wads the diff???
Hubstacks are attached to the hub. Synergy caps are attached to the inner rim.
Synergy caps generally give the yoyo a vibe though so its not really preferred, IMO. If you want to get used to practicing with a throw with the caps, then they would make sense since they’re cheaper than a $100 yoyo with stacks or caps. 
so hubstacks are better?? but it rly is based on preference right?
Yeah, it’s all preference. I think that most people prefer hubstacks, but that’s probably because more people have tried them.
Synergy Caps are just as fun in my opinion, and add a certain level of playfulness to a YYJ yo-yo. YYF hubstacks feel like they are “all business” to me. It’s not necessarily a bad thing, as I would personally choose hubstacks almost any day of the week.
ok thanks for feedback.