I am a college student badminton stringer and am looking to buy some Yonex reels based on popularity for my clients. I want to know which string you use/prefer and why (cost/feel/durability/etc)? Thanks!

This can vary per region, so you might just want to just check with the clubs where your clients are.
Here in the Netherlands people like bg65 (durability) and bg80 (performance). But not much else. But I hear very little about bg65's popularity on this forum.