Too many variables in your question, it depends on what kind of parents you already have, how many egg moves you need to chain together, which 4th gen game you're playing on, how good you are at hitting your delay+frame.Which is arguably the easier way to get quint-flawless spreads (when the Pentagon Rule is not in place) - breeding in Gen 6, or RNG breeding in Gen 4 (I can't do Gen 5 at the moment)? It seems like you basically have a 1/6 chance to get your target IVs in Gen 6 (1 in 6 being the chance that 1 IV that is NOT inherited from the flawless parent is in the stat that you don't care about - Attack or Special Attack), while you have to deal with hitting your delay and all in Gen 4.
If you've already got 2 flawless parents in 6th gen (only time you've got the 1/6 chance) I would say it is definitely easier, but if you're trying to breed a 31/31/31/x/31/31 Magikarp with a flawless Ditto and the crappiest karp you could find, RNGing on HGSS would probably be faster than constantly replacing with a better parent and hoping for the final 1/12 chance of getting what you want from 4IV+6IV parents.