I breed about everything...
You don't want to breed guinea pigs, it's a pain. they take months to birth instead of weeks. They drink 32oz of water, and pee out 3 gallons. Constant maintenance. I actually stopped breeding them "again" this year.
As for hamsters, they are all a bit different, depends on what species. I don't rack any hamsters, as they need more light than rats/mice to breed. I find it easier to breed them in lab cages. Dwarf species are total light breeders, need to be set up on a 12-14 hour light cycle to breed. Syrians, you have to keep the males seperate from the males, and can be challenging... females are little b!tch@s. They love to eat the males.
Gerbils, well, they're gerbils. They chew like ASF's, but overall they are pretty decent once you get them going. Sometimes they can take a while to get going. Very clean animals, one of my favorite.