Again, thanks for the insight. The rapid refresh rate would be tempting. I do not use flashes a lot, but when I do, I will often have underexposed image or two where the flash didn't recycle fast enough with my 600 EXs. It would be nice to avoid that. I hadn't appreciated that the LP-EL batteries were not LP-E6s and can't be substituted. So, they use the same charger, sure, that is nice, but from what I read, the LP-EL is slightly larger and can't be used in my R5, for example.