My wife is using one from Mr. DIY to store expressed milk for my infant. No fridge in her office.
3 ice packs inside, still cold from 8am-8pm. Otherwise the milk will go bad.
For all we know, these are all OEM products made in the same factory...

Mine is the smaller one that cost around RM30. A branded one of similar size cost RM120.
Depends on what you intend to use it for. Like Ozak mentioned, the environment will affect the length of coolness.
But for me, the Mr. DIY ones are good enough. Of course the branded ones might be better but the price difference does not justify the marginal difference in quality.