They realy were ahead of the time i have the SSG PII with Kahles ZF84 10X42 a friend has a SSG 69 with Kahles ZF64 6X42 that was used for trials for a replacemnt Australian sniper rifle at the time the Australian army stuck with the crappy parker hale with a fixed 4 power kahles scope and also fired tens of thousands of rounds through the AUS in the Australian Army both in the brigade rifle teams and also in general shooting when i was getting discharged i realy cooked the barrel you could not hold the carry handls/ scope realy hot.
they are all great designs and the ssg is an amasingly accurate rifle out of the box the newer AUG,s have evolved a fair bit back in the early 90's when the SLR was replaced we went from having a section with a M16 and M203 attached with the rest carying SLR,s to everyone carying AUG,s and M79's as a replacement and most were not capable of exchanging optics a few we had could have an AN PVS4 fitted and then they were realy top heavy to use and did not balance well at all. Nos with the flat top S models being the only versian made a big improvement as the scope on them is not great and the ability to use any dot or scope has them at the top.
The piston driven system works very well and they have re designed the rifle and M203 so we now have the best of both worlds. the only thing is for the lefties you need a diferent bolt head and change the side ejection port cover and you are good to go.
the best thing is that with a 20" barrel it is still shorter than a 14" M4 so more velocity with the same length.
I think thatthe NZ army has been experimenting with a 6.8 one that would be good to play with.