I have a guinea pig and they are lovely pets! Definitely not low maintenance though... And if anyone tells you they are then they're clearly not looking after them properly.
It is best to get more than one but be aware that two males will often fight while two females are usually more compatible with each other. Or you could get a neutered male and a female. It's usually best to get a pair who already know each other so you can be sure that they'll get along. Having said all that, some guinea pigs just don't like other guinea pigs. I got my guinea pig from a breeder who warned me that he will fight with all other males and I didn't want to risk neutering him so he could live with a female so he lives alone and is very happy with lots of attention.
Think about where you're going to get your guinea pig from too: adoption, a breeder, a pet shop etc. Generally, breeders will have more calm/tame guinea pigs.
There are also LOTS of different coat types. Curly, long, short, VERY long... I have a Peruvian guinea pig whose hair grows to 50cm long so has to be cut, brushed and washed regularly. You need to consider how much time you're willing to put into this.