Always used g-nocks, and although i've hit them many many many times, i've never lost a shaft while using them - and they're very cheap!
a friend of mine uses beiter nocks with tripples - it's hilarious, as he can't fit the bloody things in the shafts - even after putting them in the freezer and trying various other remedies!
he also goes through them at a rate of knots, and is strongly considering going back to good old g-nocks!!