Hey lasttango:
The boiled taste: This can be a lot of things, most likely your atomizer is clogged - or you have been vaping on it while it was too dry.
Put it under a running faucet for 2 minutes, - then blow it out with your mouth until its as dry as you can do it.
Hold a paper towel up to the end ( you blow where youd insert the cart and hold paper towel at other end ) and stop blowing when you dont see the towel becoming wet from your actions anymore!
Then insert the atomizer into your ego or any other PV, and hold down the button to activate it: while you do this blow as hard as you can directly into the atomizer ( ie. do NOT have a cartridge on meanwhile ) to cool it off, as youre doing this. Only hold the button for some 5 seconds - let it rest for 2-3 seconds, then do it again - repeat this 3-5 times.
When done, - put two drops of liquid into the atomizer - hit the power button for 1-2 seconds, then let it sit for a minute. Then insert cart, or drip = ie. do as you usually do - and this should clear the taste.
As for the stuck button: it can be a production failure. If you bought this at janty it is probably still under warranty and you can send it in. However, before doing so you might want to try knocking it ( not too violent ) against a table or something to see if the button losens. This CAN help - and in case it does not help you still have to send in the eGo under warranty. The reason why this can happen are many ; as i mentioned it can be a faulty unit or it can be the combination of you pressing way too hard, while at the same time having a button that has sharp edges inside ( because its new ) - these edges usually gets trimmed down automagically from the first 5-10 button presses - but if youve pressed it too hard from the get-go you could have twisted the button into a spot where it cant get out.
Hope it works!