Hi Rn2md,
I had the same question. I just had the Biomet implant for my left hip with Dr. Gross 4 weeks ago. I think the fundamental difference is that the thinking behind the Biomet cementless is that it removes that potential point of failure (because it grafts into the bone) as opposed to the cemented BHR where the cement could eventually fail/wear out/whatever. Having said that, I think the BHR has excellent results and almost no cases of the cement failing or being a problem. I went with the Biomet because I felt strongly that the surgeon was the primary factor in achieving the best results and I have a lot of faith in Dr. Gross based on his performance numbers and having spent a lot of time discussing this with him over the past few years. I did ask him at one point if he would implant the BHR - if that was an option - but it is not with Dr. Gross. I believe he is the inventor of the Biomet and is definitely an investigator for it. Again, the other HR specialists mentioned on this site are also excellent and I know several of them use the BHR. I have a pretty strong feeling that both are excellent devices and that we're probably splitting hairs (as long as you have one of the specialist surgeons highlighted on this site do the surgery).
I think there's a section of this site dedicated to discussing the different devices as well.
Hope that helps a little & good luck!
Chris