You'll have to own one to know the difference...
but AFAIK, Oakleys are not of lifetime warranty... it is a misconception by many people... Oakleys are only 1 year warranty free and only if you keep their warranty card, stamped by an authorized dealer and you'll have to keep your receipt on which Oakley will do the repair with no questions asked. However if it is more than a year, Oakley would still do the repair for a fee of $30... but judging from the impact resistance of Oakley shades, wat are the chances of it needing a repair...??

Currently wearing a Half Jacket, thinking of getting a M-Frame(Hybrid S) and Juliet in the near future. Btw, their prescription glasses are also great, esp. Wiretap...

P.S: there's no point going around to compare the prices of different shops... I think Oakley Singapore does very strict control on the prices of their shades and glasses, so not much of a difference.