Fancy, guinea pigs have a lot more meat on them than rats do. And I've never kept rodents as pets, so I don't have that issue bothering me. Rats are more sympathetic pets in my opinion though, the guinea pigs just seem passive, and I find it a bit cruel to keep them in such small cages as people usually do. I actually have one fond memory of rats, there's a science center near Helsinki where we went when I was maybe 8 or 9. They had rats that where trained to play basketball. After their "match" I got to pet them, and one of them crawled up my sweater sleeve, and out through the collar. It was pretty cute.
This brings another story to mind. While Karin was still studying, they had a animal handling session with lab mice. One of her classmates, while handling them, was bit in the finger. This was followed by the Finnish equivalent of "Motherf***er!!!" being screamed and a mouse flying in a huge arch. Karin handled the bites a bit better.
Rats have the worst bite. Very painful and bleed for agers. I used to breed them...