I have to agree that there are pros and cons to each decision you make. I got my 2nd one, Foxxy, 1 year after Diva..who was fully trained, etc. and there were times I wish I had gotten them closer together. It's just like if you had a litter of puppies and decided to keep 2..
They grow together, training is done together,etc. It just depends on your patience level also. If you know what you're getting in to, double the time, double the trouble, but at the same time, and you're willing to be patient with it all, i say Go For It!