printbus......yes i have only used the abs. i dont ever print in pla so i have no input there. one thing to note though is that the bumps you speak of are 10 times more likely to happen in black filament than any other color. i have seen this from many brands. one of them i ended up working with the extrusion co for awhile to figure out the problem. it is caused by the black colorant making the plastic sticky. the plastic slowly builds up on the nozzle of the industrial extruder then the blob catches onto the filament when it gets too big which then gets spooled up. not that any of this has any usefulness to you, me or anyone else here. we just know we need bump free filament. ive been through atleast a dozen rolls of toner abs and every roll has been spot on accurate even the black.