I didn't find airfare to Cur a whole lot different than Bon. The only advantage that I saw was in reasonable flight times and that's from NYC. I'm in a bad spot to fly from (Albany, NY). And, no it's actually worse and more costly driving to Newark/JFK/LaGuardia. I've tried it several times and it sux and overall saves no money.
On the other hand I can fly nonstop to Ft. Lauderdale for <$200 roundtrip with a couple of hours flight time from Albany. Rent a car and drive to Key Largo, stay at a hotel, eat out, and dive with Rainbow - 2 morning, 2 afternoon dives a day for a lot less than Bonaire would currently cost.
Don't get me wrong, I love the freedom of diving Bon and I'm not comparing Bon to KL. I'd much prefer Bon, but KL is so much less expensive right now, and there are no customs lines to deal with, no connections, and with a direct flight I won't have to pack a carry-on because It's going to be hard for them to lose my checked bag. Really critical stuff (computer, perscription mask, reg) will fit in my "personal item".
Being philosophical, I won't have to decide when or where I want to dive - that's decided for me. Yeah, I know, that's a real stretch. Like I said, I would much prefer Bon. I just can't justify the current cost nor could I endure 18-72 hours either going or returning.