Unlike the others, I've had delayed bags on international flights 4 times: once to BKK, once to London, and twice on a recent trip to Iceland -- lost both ways, but both due to domestic Delta rather than the international part. Oddly, it was always the same bag, which I only used on international flights, and won't again.

Anyway, even with this experience, generally you will be ok with checked bags. If they get delayed, they'll usually catch up in a day or 2, and that is the key. Carry-on a change or two of versatile clothes, small amounts of necessary liquids, and relax and have fun.

Of course, I will never check bags myself on an international flight again.