I have been wearing it for 3-4 days now.
Firstly, regarding the size, I bought 2 sizes larger compared to the size of the shirt I usually wear and it fits very well. (I usually wear XL-2XL short-sleeved shirts and I bought it in 4XL. I am 1.88 meters tall and weigh 110 kilograms).
Secondly, it is short (the zipper is at the waist).
Thirdly, in temperatures ranging from 19-32 degrees Celsius (without the lining), it is very good. It cools nicely when moving at speeds of 50 kilometers per hour and above in 32-degree weather, and you feel a slight chill at 19 degrees, but it is manageable, whereas with the lining, I don't think I would feel anything!
At lower speeds, with 32 degrees for a short distance within the city, it is still fine. Now, for a whole day in the heat with speeds of 30-40 and 32 degrees, I think someone would get hot.
What is certain is that you feel cooler than if you were just wearing a short-sleeved shirt, as the sun does not burn you.
The construction quality seems very good.
The neck button is adjustable, so it will suit most people.
I consider it an ideal, affordable, and reliable jacket for its price, and you can comfortably use it from March (with the lining and a slightly thicker shirt) until definitely mid-November.
Otherwise, it is very nice. I got it in black.

Update. With 16 degrees, in the evening with humidity in a village, wearing the lining and a short-sleeved shirt, I did not feel cold.
I only felt a little bit of air on the areas of my hands due to the short sleeves.
I want to say that you can wear it very comfortably, especially in colder places.

It looks very good quality, I don't know what will happen over time. The protection seems satisfactory, while the ventilation is also satisfactory... I wore it at 35°C and didn't feel any hotter than with a short-sleeved shirt. In fact, I felt better... At traffic lights it was tolerable, while with the short-sleeved shirt I couldn't stand waiting because the sun was burning me. I also believe that the fabric will perform satisfactorily in case of sliding.
Be careful with the color... The Grey Fluo is not like in the photo, but has the color of ice... almost white. I returned it... The Dark Grey I ended up with is exactly as in the photo. I'm posting a photo of the Grey Fluo.
Because I work in a hospital and experience the summer traffic accidents, I recommend everyone to buy a summer jacket and not just that... Protect yourself as much as you can... Personally, I also bought pants, knee and shin guards, gloves. From my experience, I see more injuries to shoulders, elbows, shins (lower leg), burns from the asphalt, followed by knees and ankles. I won't comment on where most people who don't wear a helmet end up...
(Sorry for the rambling)