Hi Shoebz,
Congratulations on making a new friend. I remember how frustrating these things can be. You are using a Vision style clearomizer and they do have some quirks to them. The wick material varies by manufacturer as does the actual construction of the head. What I found was that I had to do the "twirl" with some of them. Hold the device upside-down and swing it in a circle after filling it. Press the button a couple times while you do that. This 'primes' the coil and helps eliminate any leftover oil and such from manufacturing (likely the source of the foul plastic taste). You may have to do this more than once depending on the juice you're using. Some thicker juices just don't work well with these style clearomizers. If that's the case, try one of the bottom coils, you can tune them a little easier and you will always have juice on the wick (contributing to the dry, burnt taste is the lack of liquid under the coil).
I agree with the others, the source makes the difference. I like Vision genuine products in this style and I've tried Smok and others. In this style Vision wins. For the ViviNova style, Smok wins. For the bottom coils, Kanger wins. The point is, each style has its best-in-class manufacturer. And even then, given the size of the production runs, you can end up with a rare dud.
Good luck and Vape On!