I was one of the first people home brewing well over a year ago with EO ont his forum. Not that it matters, but I have a lot of experience with homebrewing, and now using Stallion products with EO. I made painless 220mg/ml Primo in pure EO a while back and had it lab tested - it came out awesome and was completely painless. Unfortunatly ordering powder from overseas is not a risk I wish to take anymore, so I got a domestic supplier for a product line I like.
So back to the EO - I made 100ml of that Primo I spoke about and used 50 for the first cycle, and 50 later down the road. I never noticed the stopper on the vial degrade, and I had nothing but smooth injections.
So in conclusion - If you homebrew - Spend the extra and use EO if you are making something high concentration or something that is usally painful (Prop for instance) - and if your UG source offers EO as an option - pay the little more it is certainly worth it.