Spaying and neutering

I've always been a proponent of spaying and neutering, but I've read some stuff recently which has given me cause to rethink how I feel about the subject.
I totally agree that there are too many unscrupulous puppy mills, and stray dogs, and a horrendous overpopulation which I do not want to contribute to. But on the other hand, there are some risks in spaying, not only the surgery but afterwards.
The problem in making a wise choice is that many people have an agenda and a rational conversation is not possible in many places. It is hard to express concerns when you agree with some of what others are saying but have done research that causes concerns.
We are each responsible for our dogs, it is not always clear what the right thing to do is. I'm certainly not trying to tell anyone else what to do, I'm just expressing my own misgivings. I have an appointment this Friday for one of the dogs to get spayed, I'm not sure I will go.

Here is an interesting article:

healthypets.mercola.com/sites/healthypets/archive/2011/09/06/one-two-possible-reasons-dogs-live-longer-in-europe.aspx