Personally, I prefer flying endurance 3. Because Fei 3 has powerful functions besides wrist heart rate measurement. There is another important factor. Fei 3 looks good on you, and 235 looks like an electronic watch anyway. Fei 3 can be competent for any occasion after wearing the right strap. His information reminding function is very practical. And 235 is mainly for measuring heart rate. If you are a marathon enthusiast or have a fitness plan to lose weight, you can use your heart rate, but it has no effect on your exercise. I once ran half a horse with a heart rate belt, and finally I could hardly feel the existence of the heart rate belt. But flying 3 is more expensive than flying 235, right? You should consider the budget.