Steve,
Yes, I could see if the cement was mixed improperly it could be an issue, it's not usually. The amount of cement can cause issues too.
I agree we are the "Guinea Pigs" for uncemented femoral heads, but keep in mind I said cemented is the gold standard and they do seem to hold up well.
I am on the side that if uncemented becomes the gold standard it will do so because it's simply one less step in the operation not as much because cemented failed because it looks good so far for cemented so I really do not consider you a "Guinea Pigs".
I picked Gross not because of his uncemented femoral concept but because of all of the positive feedback people gave me about him and his staff, my second choice was a surgeon who does not perform uncemented. I had my choice of cemented or uncemented, Gross would have done either on me, but I chose what made sense to me.
As it looks right now I think uncemented will be the gold standard assuming I and others don't have stuff falling out.
Chuck