I actually have these bulbs.
If you look closely at Sanjay's results, the AB 10/13Ks on a standard magnetic (probe) ballast actually have slightly more PAR than the Iwasaki 13K bulb (73 vs. 71). It's on an electronic ballast that the Iwasaki bulb goes crazy bonkers for PAR (87).
Visually, the ABs give a great crisp bright white light. Still breaking mine in, but I am very happy with them. I wanted the Iwasakis but given that I have a probe ballast and I'd have to get them shipped from the States to here in Canada, I went with the ABs.