We had gerbils as a kid and they were kinda awful. Mostly because we were kids and my mom had no idea how to care for them and neither did we. They do require a secure cage (ours always found away out somehow). They are social little things and are happy in same sex pairs otherwise you can quickly find you have 30 gerbils when you had originally only wanted 2. They require a lot of patience in taming, and if you pull their tails and they feel threatned their tails will come off. My little brother (He would have been like 6 at the time) had the male gerbil (we called him donny) upside down with the tail in one hand asking my dad to glue it back on. Some people absolutly love gerbils. They are active both during the day and at night. They will happily eat any paper product to make bedding. Give them a toliet paper roll and it will be chewed to pieces in hours.
Here are some links to help care and find out info on them: The Humane Society
Gerbils : The Humane Society of the United States The American Gerbil Society
AGS Gerbils Home and here was a pros and cons of Hamsters vs Gerbils from ABC Gerbils:
gerbil - gerbil versus hamster
We personally are having much better relationship with our hamster than the fiesty engergetic gerbils.