I tried two different replacement head brands for my Sonicare electric tooth brush. Neither of them were close to the quality of the real Phillips e series OEM toothbrush heads. For a few dollars more, I can get the real product and have my teeth feeling like they should feel: clean and fresh too.
BEWARE of 3rd party junk brushes. I tried a brand-X generic and wound-up throwing them in the garbage-can. They felt 'wicked' on the gums...way too stiff... felt like a wire-brush... not good. This is my 2nd 8per/box order. Get the real thing.