I've never heard the thing about using only Brother bobbins. I didn't even know Brother made their own. I own 2 Brothers, a 270D and a PQ1500. I can use cardboard bobbins in either. However, if other owners of your particular machine say it's picky about bobbins, then I'd listen.
About thread.... I'm a HUGE fan of Bottom Line, which is a Superior Threads product. It's a 60 wt poly, I buy it by the 3000 yd cone. It's pretty much all I use anymore, except when I use my little 270D. Can't put a cone in her thread cartridge.
