I am getting ready to re-plumb and I have seen quite a bit in here about using the 'blue' pvc cement. I have picked up some Oatey Rain-R-Shine blue cement. The spec sheet for it states that you don't need to use primer. Should I? If so, would the purple primer work OK?

I have seen a lot of spa manufacturers use cement similar to what you are describing. I haven't used it personally, and primer SHOULD be ok with it. What I use is primer and standard pvc cement. I just like the idea of cleaning the pipes before cementing, verses just applying a cement that doesn't need primer. I haven't had any of my assemblies leak using the old "tried and true" method.