I can possibly offer somewhat of a unique perspective to the OP's original question, which was more related to how one feels after quitting vaping than cigarettes.
When I started vaping a month ago, I hadn't smoked a cigarette for 3 years. However, I had been using Copenhagen tobacco, but haven't touched the can thats been sitting on my counter since I started vaping. I started vaping strictly to help with the nic cravings of quitting the tobacco.
When I first began vaping I had light headaches (probably dehydration), occasional sore throat, and about a week in a respiratory infection for a few days. It has all but cleared up now and vaping seems to have little side effects on me other than the constant drinking of water and trips to the bathroom to get rid of the water. I do occasionally get a bit of a cough that I didn't have when I just used the tobacco, but nothing like when smoking.
I will say that vaping has had a minor ill effect on my breathing capabilities. A trip up the stairs in my house used to be a breeze (ever since a few months after I quit smoking). Now I do sometimes get a little winded. It isn't as bad as when I smoked cig's but it is more noticeable than no vaping/smoking at all.
My personal opinion is that if possible we should all strive to quit the tobacco AND the vaping, if we can. At this early point in my vaping endevour I don't know if that will be possible for me, but I'm going to try. If not, at least I believe vaping to be better than any of the tobacco products.