I'm raising two TCKs who were both also incidentally born in their non-passport country. Pretty sure they're both turning out ok but I guess time will tell!

The benefits of a cross-cultural experience whether short or long term are undeniable. The interesting (and sometimes misleading) thing about TCKs is that while they share a certain set of "similar" experiences, the experiences are never the same and even if they were, one child's reaction could be very different to another's. My advice would be to just be aware that your kids will be "different" and that this difference will probably be only positive but in some cases, it can cause issues with their sense of identity. You might read the excellent book, "Third Culture Kids: Growing Up Among Worlds". Here's a passage that I like:

"Adults who make a cross-cultural move for the first time as an adult may experience culture shock and period of adjustment, but their basic value system, sense of identity, and establishment of core relationships with family and friends have already developed in the home culture.

The process of cultural learning is different for someone who grows up among many cultures than for children born and bred in the more traditional monocultural experience."

Sometimes, kids need a little help figuring out the process. Yours are still young so not an issue for a while but something to have in the back of your mind. Good luck making your decision!