Try Savage Worlds with the Sprawlrunners book. It has rules for everything you'd want in a Shadowrun game for Savage Worlds, so you just cut out the non-human races and magic and bam: Cyberpunk with better rules.

I played in a Shadowrun game that we converted to that ruleset and it rocked.

the armour system is certainly realistic, but it's not exactly fun

The rulebook sucks but I kind of dig the actual ruleset once I made a few cheat sheets.