G700s is better for gaming but battery is only 12-16 hours depending on settings compare to g6002 which has about 200 hours on Performance mode. However you need to buy batteries for g602 whereas on g700s you can recharge (they come with a single envelope battery AA ) or wired mode.
They are both great mouses so you cant go wrong with any of them but personally I would go for G700s as it is wider and bigger than the G602 and does not curve in as deep at the thumb rest. It is also substantially heavier than the G602. Whether that's a pro or con, depends on you. The G700s has better internals regarding the report rate, DPI etc. Although I cant notice difference between 500Hz vs 1000Hz. Hope this helps