You actually handled an SA80? May I know when this was? And what
version? A1 (pre-HK mod) or A2? As far as I know, the A2 version
had pretty good reviews from troops in the field.
I had a friend who graduated from Sandhurst; he had some complaints
about the A1 version, but said most of the criticisms were based on
second-hand information that got passed round and exaggerated. Yes,
the A1 had problems; no, that didn't stop it from going 'bang' if
you took care of it. A bit too much care sometimes...
For me, best rifle handled: CAR-15.
Light, reasonably accurate in CQB and VERY ergonomic. Short length
is a real bonus, especially in CQB.
Cons: Not very accurate at longer distances... Or maybe im just a
bad shot 
Worst rifle? I've only handled the M16, CAR-15 and SAR-21. Guess I
would have to say that the one I like least is the SAR-21.
Sexy looking gun, but weighs too much (kevlar plate in the
cheek-rest?!?!), LAD zero goes off after prolonged fire cos it's
placed right next to the muzzle, reloading magazines is slower, not
very ergonomic. I much prefer the M16 style fire selector using the
thumb.