[chris220]

what is the difference between them??
Pls give me some comments..
I want to buy one of them....

[Therocks]

For compact size I would like S4i, S4i size is good for gril ( Personal opinion ). user interface is friendly
So I selected S40...Because S40 size is better for big hand user 手大朋友.....
S4 not idea.....

[suet1225]

for general, s40 is the best among the 3, if you consider all the aspects

[twbchang]

我都認為 S40 較為好用，介面也是較易操作，性能比 S4i 更好，不過只得1.6"芒。
但對我來說，輕,細和1.8"芒比較重要，所以要買S4i。

[skyey]

S40 is also good for girls, the size is just a little bit bigger than S4i, and only this model can use 2A battery which is quite convenient.