I never played long enough to build anything real heavy cyberedr, but my impression (from like 2nd Ed., heh) was that you had to be in the very highest income bracket to afford cyber limbs, if at all. Even wired reflexes were expensive, when they (apparently now past tense) were the rage.
I tended to make characters that either just squeaked by or quickly croaked in major firefights, but if they squeaked by then they would get the mission payoff and beef up gradually. Ironically, players seemed to like some of these characters for having the spunk to be around at all (their tougher characters tended to intimidate or disable them out of pure contempt, though).
Characters in D&D get levels... characters in Shadowrun get cyber, was pretty much how I thought of it. Although in sustainability terms, I never have been really taken with the idea of a super mechanical type. I'm sure there are some very simple ways to handicap them or just plain shut them down. Something like EMP, enough tin foil and a power outlet, big magnets, whatever.