Most guinea pigs will be happy to drink from a water bottle or from a bowl, though it can be difficult to switch drinking options once a guinea pig gets used to a certain method.
It really comes down to your preferences. There are benefits and drawbacks to bowls and guinea pig water bottles. Bowls are easier to clean, but they can get dirty more quickly. Guinea pigs don’t mind getting a little messy, and you may find bits of food or hay floating in the water bowl. Your piggies may also accidentally flip over lighter-weight bowls, which not only makes their enclosures wet but could also lead to dehydration if you don’t refill their bowls quickly. This is why it’s a good idea to use heavy water bowls.
Water bottles don’t require you to open up your guinea pig’s enclosure in order to fill. They also sit outside the cage, leaving more room inside for guinea pig toys and habitat accessories. However, they are more difficult to clean and may begin to leak over time. You also need to check water bottles every so often to make sure they are functioning correctly.