Off the top of my head, Qawi. Wasn't until the advent of Holyfield- and at the second time of asking- that he really came up short. No amateur experience, a midget, made a mug of Leon Spinks, went deep with bigger more experienced guys like Michael Spinks- who was damn near a foot taller. Fenech might have been "better", but Qawi was greater.
I think it's Fenech who has the argument as "greater," but purely going off peak, I think the Qawi that wrecked guys Rossman, Saad, and Martin was a better fighter than Jeff.
In terms of achievements I would say Fenech. Skill wise and H2H I favor Qawi, just had better defense and counterpunching abilities.
Qawi is the last 5'7" man to stand in with and really battle a future heavyweight champion. Unless you count Montell Griffin and i don't.
I think the achievement of being the World Cruiser/Light Heavy champ at 5'7" and no amateur experience is an "achievement". The guy was the same height as Fenech. Then again not everybody has their own WBC Watch
Fenech was a pretty versatile and adaptable fighter in his own right though, even if his style was rougher around the edges. I'd probably rate Fenech as greater based on achievement, but better is more comparable and debatable IMO.
Fenech was versatile and had a much higher ring IQ than given credit for. Both these guys had insanely high ring IQs for attacking fighters, though I would say Qawi had the higher ring IQ.