I find keeping 10+ name brand pro saws and another 10+ units like pole saws, hedge trimmers, bk-pk blowers, clearing saw, trimmers etc is hard enough when used daily in a work scenario. Everyday they need to function properly & work. It surprises me how long pro equiptmemt lasts with relatively basic maintenance. Once you introduce Chyna top or bottom end component's or any really for that matter you compromise the unit. I use China rim sprockets & chain roller catches, that's about it, well that's about all incan afford to use. OEM may be expensive up front but its smart business to buy them when you've got saws & other gear thats been used daily for half a decade with only minor issues. Start using the China & all that changes, you end up with down time, frustration, not being able to finish jobs... its just not worth it (for me). $30 cylinder kits sound amazing until you try using them 5 days a week.