It really depends on the response to your Kickstarter as to what makes the most financial sense. POD books are so much more expensive than books in a traditional print run (around 3x the cost per book, or even a higher ratio if you order a larger number of books) that how many books you buy affects which direction to go. Usually the tipping point is around 300 books or so; if you think you're going to need 300 or fewer, you're better off doing them POD. If you're going to need more than 300, it will cost you less to order 1000 copies of an offset print run than for those 300 POD books. This includes not just your actual pledges, but also your forecast of additional sales to distribution or elsewhere.
We've done both in the past, and in fact sometimes both within the same Kickstarter project. For example, when we did our Pirate Campaign Compendium, we only needed about 150 copies of the Pathfinder RPG version, so those books were fulfilled as POD. On the other hand, we had over 300 pledges for our 5E version, so we did an offset print run for those. After-Kickstarter sales have certainly borne out the trend, we've nearly sold out the entire print run of 5E books, while we've sold far fewer of the Pathfinder RPG books.
For a project like this one, we have clearly different numbers of pledges for different systems, you never know for sure whether any one of them or all of them might warrant doing a full print run. We have ways to keep shipping costs down to most countries by using Amazon as our international through-shipment service, so it's not as bad as straight-up USPS shipping.
But the compromise solution is simple enough and we're doing it with this project: Even if we do end up doing a print run (which at this point seems unlikely), for any international customer who'd rather get their books POD to save on shipping, no problem! We can totally do that!
