Some love it while others bodies can't tolerate it. It's known to turn the injection area red, warm, swollen and have abscess-like symptoms for the ones who can't handle it. Granted, it does allow for higher concentrations but honestly I don't give 2 shits about shooting some painful ass 400mg test!
If you are going to use it, I would start with a very small percentage and work up from there. It is pretty intense stuff though, leave a cc of EO in a syringe over night and see what it does to the rubber stopper! I've used only 4% which I can handle but my buddy hates the shit even at 4%! I find it to be 50/50 with whose body likes it and whose body doesn't so it's all up to you!