I have 3 young puppies and am very happy with my decision to add to my fur family. I'm actually going to be adding another yorkie into the mix in about 6 mo-1 yr. I think one of the biggest questions to ask yourself is, do you have the money for double the vet bills, double the food, double the grooming ect? I know it got much more costly when I got two, then three =)... more clothes to buy.. more grooming to be done, hehe!
Honestly though having two was no adjustment at all for me. It's more training, but other than that it's a lot of the same. My biggest adjustment was going from two to three since I only have two hands
that's where a coupler comes into play!
Good luck with whatever you decide