My kids are using SPI but they seem to be a bit heavy.
I also found so !
Since last October, I changed another one for my girl. It is not any specific brand commonly known, is just a very general one bought from Jusco by my relative.
I believe my girl needs a school bag which is light but the material is also strong. Forget about the things like 護脊, 人體設計 since these will make the school bag itself unbelievable heavier and my girl, in fact, only carries the bag on her back less than 15 mins a day.
Since last October, I changed another one for my girl. It is not any specific brand commonly known, is just a very general one bought from Jusco by my relative.
Seven is very good. My son is a P6 student, he used a small size one from P1 to P3. I changed a bigger one for him in P4, it is still in a very good condition, he can continue to use it for S1. It is value for money.