if your talking about platinum series primary arms i think glass quality would be the same, the only real difference is coatings and features, if your talking about the $600 primary arms "standard" model i think if your a scope snob the trijicon would work better for you...... buy once cry once, if you want "good" quality for low price then the $600 model will suit you fine.
between platinum and trijicon, i would take trijicon all day long...... and have 1 on order (delivery next week). i also own the mk 6 1-6 leupold
platnium weighs 26.5 oz's (34mm) - eye relief 3.86 - 3.98 inches
trijicon weighs 25 oz's (34mm) - eye relief 3.9 - 4.0 inches
standard PA weighs 16 oz's (30mm) - eye relief 3.30 - 3.50 inchs
leupold mk6 1-6 weighs 17 oz's (34mm) - eye relief 3.7 - 3.7 inchs
lots of things to think about, if you have the money, buy the trijicon, if not buy the standard $600 primary arms one and spend the rest on ammo.
mounts i am using geissele and kac, but i hear the leupold 34mm is nice to..... all 3 are somewhat easy to get in canada with the geissele being the easiest thru armseast