SPCA spaying and neutering?

Has anyone taken their pets to the SPCA to neuter or spay? I've heard they're excellent, cause they do it a hundred times a day and they're very cheap and you're supporting the SPCA with the money.

I thought about using the spay/neuter clinic for my last rescue, but the wait time was several - 8-10 -weeks and she had already gone into heat once so I brought her to my vet for the procedure.
Thankfully my vet gave me rescue rates for all her initial care and testing including her spay so I was lucky.