Gerbils are great pets. They do best with some gerbil company, are fun as heck to watch (especially after their cage/habitat has been cleaned), will respond if you play with them/hand train them, and are easy to care for. And they are really cute. My son had gerbils when he was small; they were a lot of fun.

And if you get a bunch of cages/habitats, reconfiguring the gerbil abode becomes an interesting engineering project! We had nine cages in all, and would have has many as eight at a time making up the gerbil complex. (We always kept at least one cage separate in case of illness/need to transport/stashing for the complex cleaning spree.) Lots of tubes and levels and places for the gerbils to be.

I have a friend who used to have rats as pets and liked them a lot. (Now she has cats, so ... no rats.) But gerbils... are definitely cuter!