My experience was relatively easy. Budget constraints made it tough-love easy; I could afford an e-cig or analogs, but not both. I took a chance, and it worked for me.
The first couple weeks were...interesting...to say the least. My lung rumble cleared up almost immediately which was the impetus that started me up in the first place. But the morning cravings were murder. Trying to restabilize the nicotine levels in the blood after sleeping is harder with a vape, the nicotine isn't as readily absorbed as it is from smoke. I'd nearly suck my tank flat for the first two hours every morning. Fortunately that will ease over time, but I don't think it ever really goes away, I still hit harder in the mornings than any other part of the day. Drink your water.
I was lucky in that when my lungs started cleaning, they did it subtly instead of making me cough incessantly like happens for some people. The first week was comfy, no real big changes. The second week and for a couple of weeks after, I couldn't utter a squeak without clearing my throat first, lungs would sweep the garbage up to my throat and park it there for me to deal with. I still get that, but it's not constant anymore. Drink your water.
I got the joys of going through puberty again, too. Smoking suppresses testosterone, the body has to ramp up production to compensate. In sudden fashion, the suppressive effect of smoking vanished for a body accustomed to compensating for it and hormones became, for a time, over-abundant. This is why people get the "quit-zits", an increase in acne. Comes with all the other pubescent effects too. You'll discover those on your own, no need for details. Drink your water.
The main carrier materials in e-juice have a laxative effect. You will be astonished at how regular you suddenly become. A LOT of regular. This is temporary, it will taper off, but your movements will be considerably easier, constipation will be a thing of the past. Drink your water.
You are going to experience sleeplessness. You just aren't going to want to go to sleep. Nicotine is a stimulant, but why this effect is so pronounced from vaping when it wasn't from smoking is a mystery to me. You are going to have to keep multiple nic level juices handy. High nic for morning cravings, regular nic for all day, very low nic for evening time or you are going to become VERY familiar with what's new on the late-night infomercials. Drink your water.