The Flip Flops are very convenient and comfortable! Originally, I had simply intended only for showering on holiday and in the swimming pool. But they are perfect because they can wash very well and as they dry very quickly. However, Flip Flops are so comfortable that I also like to wear so well, and that even though I have trouble with sweaty feet (and that's why I do not like to wear sandals because I can cope with almost any material!). The material here is certainly not nearly as unpleasant as you may think.
One star deduction there is that they are a little uncomfortable after a run-time between the toes. But it has its limits - it remains a recommended shoe! The price-performance ratio is right.
For size: sizes normal! I usually just size 39.5 and then take fundamentally size 40. This fits well here.