"...I have had, however, the male/female thingies fail on me..."

So have I, but rarely. I use them on my normal carry keys (a pretty large bunch of keys and stuff by the way), and have been using this particular "pull apart" for probably ten or eleven years now. The trick is to buy quality, usually from a lock/key shop. The ones you see near the checkout at WallyWorld are usually not high quality, those will normally fail much sooner. I have had worse luck with the little gate springs breaking on the "not for climbing" mini-biners...