My understanding is that a few things will be known after Phase II trials.
For one, the Phase I trials showed hair growth in 5/7 patients, but the hairs were thin. I don't know if they were vellous or not, but I did hear that they were thin, meaning that maybe they were thinner than the other hairs on the rest of the head (side and back). So hopefully Phase II trials will test a greater dosage of injected follicular cells, which will grow hairs that are as thick as the hairs from which the cells were taken.
Another thing they will learn is how the injected cells grow in completely bald areas, AND how they will grow in thinning areas of the scalp.
I would hold off on getting an hair transplant until the results of the Phase II trials are in, which should be at the beginning of 2008 anyway, according to the recently posted web links.