Ok the Steyr AUG is the only one on your list I have any experience with so my opinions might not be all that valid but sure what the hell.
Our AUGs are Austrian built so there was none of the quality issues associated with the Australian/Malaysian built ones.
Reliability wise its pretty dam good so long as a half decent cleaning job was done on it the last time it was used. (True of most weapons though.) Over the course of 6 years usage I had around 7 jams with it using live rounds. All bar one on the same weapon on the same day. It was a common story on the firing line that day so I figure there was something up with the ammo.
On blanks though it was fairly common to have problems. Though most were solved by the first step in the ia drill. On three separate occasions it double feeded though which necessitated taking it apart to clear. Simple enough push the body locking pin through and bobs your uncle. It should be noted that of those three occasions two of them were down to operator error (one mine the other my number 2). What happened is we didn't realise it was a double feed and kept cocking it so the two rounds got wedged into the point where it had to be striped.
I never used it in a dusty/sandy climate but I know plenty who have and they had no problems with it.
With regard to ruggedness its a very solid weapon. During the acceptance trials the army called Steyrs bluff and ran over one with a truck. It still worked perfectly afterwords. There was just a small crack in the stock. I have only ever seen one broken, the body locking pin fell out due to worn parts. The weapon was 15 years old so I'll forgive it. I also heard of another being broken by someone falling into a tree while running down a hill. Used the rifle to protect them selves and broke it in half so the story goes. The springs that are part of the adjusting knobs of the optical sight fail from time to time.
As for designs flaws the only things I can think of are the placement of the front sling swivel (the sling tends to cover the cocking handle because of it.) and the fact that it is real easy to cut your little finger on the front left corner of the housing group when cocking the rifle. Have a small scar from doing it so many times actually. Oh there is one more thing now that I think of it. The clip on the newer rifles that joins the sling together is a pain to undo unless you have something to push under it like knife.
As far as other things go. The EBS are next to useless. They are cast onto the top of the sight so are non-adjustable. Though they are only intended for when the enemy are up close and personal. The bayonet could be better as well. Breaks very easily.
As for accuracy its pretty dam good. I have seen persistent 1.5 - 2 inch groups at 100 yards (don't ask our ranges are old and our government cheap).
Though for most bods 2 - 4 inch groups are more normal at 100 yards.
Hope thats what you were looking for because its all I got
