which is better: advanced 8 on GEM or nexstar 8

asuming otas are the same, is the upcoming gem mounting better than the single arm fork mount of the n8? better than the dual arm mount of the n8gps. okay, i don't need the gps, but that's the only model that comes with both arms of the fork. do you think the gem mount will be better than the n8 or worse in terms of stability? tracking? photography? in general what are the pros and cons?

thanks,
allison.