I have bought a V version. Waiting for it to be delivered, so I can't be any help regarding the pros & cons of the E, but I went for the V on cost grounds, plus I did not want the problem of finding a suitable place for the E control panel.
I had a Scottoiler on my last chain drive bike (10 years ago), and I didn't get on with it very well - I am hoping for more success this time!