Joking aside, I prefer 0.28g BB Bastards. Have used them in TM DE, TM 4.3, PTW MAX SCK, PTW MAX Factory QC, TM S-System... never had a problem. I find the 0.25g a little light for my preference, but then I'm a stickler for consistency - even with the wind blowing I'd like to know precisely where the BB is going to curve.

Prior to BBB I used Guarder 0.28g and never had a problem with them either, but PTWs are pickier with what they eat.
Going to try the 0.30g BBB this season and see how it stacks up against the 0.28g outdoors on a sub-400 AEG.