Might consider what you look for in a small fur pet. Female mice are wonderful,should be kept in pairs or more, a male can be alone if you have the time to give it companionship. Smart buggers and social.
A couple or few gerbils would make sure life is never boring, like mice a bit but an active animal, they could use a roomy cage, I loved my trio. They love to play.
Hamsters have to be alone, cute little fur balls, great little companions.
Takes time and patience with any of these and usually a trust training and bonding period for them.
Only cons is it is a responsibility to care for them properly, learning about their keep and behaviors.
Had over a dozen mice in my day, 3 hamsters, and a trio of gerbils, not counting two ratties and a vole.
Read about all of them, then decide for yourself, each one has several keeping forums you can learn from.
Often when I am tossed with decision, I get both or all. One point, I had a hamster, the gerbils and 5 mice plus two rats.
Wouldn't hesitate to keep them again. Generalizing, rats are favorite, and the closest bond with any was a single male mouse. Loved every one of them.