Diapers! HAHAHA!
Aiya, no need think so hard la. Choose the oil weight based on your cars requirements. If the service manual says 5W30, then stick with 5W30. Whether mineral, synthetic or fully syn totally depends on the way you drive. If you're not a heavy footer and don't go track or drive like a madman up Genting Sempah, then you're all fine with semi-syns or minerals as long as you stick to the recommended OCI.
If you're a heavy footer and all that then fully syns or even ester based fully syns would be the better option since they are more resistant to oil breakdown and have better heat resistance and dissapation and all that.
If your car is an old junk and has never smelt fully syn oils before, don't be a wise crack and use fully syn unless you're prepared to replace broken oil seals and gaskets.
If you're a mix between heavy and light footer, then semi-syn is plenty enough or if you have the budget go for fully syn. No harm done.
If you're a broke bugger like me then you'd go for whatever oil that suites your budget. If you're not a broke bugger then just buy whatever type that tickles your fancy.
If it's good report it here, if it's bad report it here and let everyone know your feedback based on your car type and driving habits.
Ixeo taiko : Not all fully syns can last 1 year la. Try that with Royal Purple and you might find yourself with a supremely rough sounding engine and bad fuel consumption after about 5 to 6 months (or 8000km whichever comes first). Well, that was the case for me anyway.