I've only been using an E-Cig for about 3 weeks myself, so probably not the best person to help out, but here are my views...
Yes, E-Cigs taste 'funny' when switching from regular cigs. I guess this is just down to them being completely different. You quickly get used to the taste, and I am sure you will soon find that you actually prefer the E-Cig taste to that of regular cigarettes.
As others here have said the carts that come with E-Cigs seem to be generally rubbish. I would get what you can out of them, but then switch to liquid as soon as you can.
The liquid has a much bolder flavour. So far I have tried Totally Wicked Cherry, Liquorice, and Coffee. Cherry had the strongest flavour but Coffee is my favourite and the one I feel I will settle on as my regular smoke. Though dont expect it to instantly have a strong taste unless you have run the atomiser completely dry. Have to get rid of what is in there already before you get the full effect.
As for the headache, I wouldn't be surprised if that is down to you simply having more nicotine than you are used to. From what I can tell Nicotine headaches are common for new users, especially during the stage of using it constantly trying to work out the best way to smoke it. Your body will adjust and that will pass quickly.
As for the amount of vapour... just stick to it. I can't explain it, but either my atomiser has 'settled in' or I have just learnt how best to smoke, because I constantly get way more vapour now than I did at first, with the same atomiser and battery, and when I put one of my few remaining original cartridges on. Just give it a week or so and you will find things fall into place.
Overall, just stick with it. You will soon find yourself loving it and getting a good smoke from your E-Cig every time
