Nicotine is very addictive and so switching, for me, was a big deal. I knew some acquaintances and I observed and listened. I did some reading, too. I have to say, I did not encounter ECF right away. Anyway, I went to a local shop and he set me up with a mid-level (for the time) mod and very simple tanks that just took a factory-made coil. Oh, two batteries, a cheap charger and free juice in tiny bottles to try.
I searched the internet for the items and found that I paid double, but they were valid in reputation. One of my acquaintances said to get a spare and so I got an Innokin MVP2 and Protanks on the internet. The reason I say that, is that a B&M has a lot of overhead costs. Building rent, employees, etc. Anyway, prices were a lot lower on the internet.
I have always appreciated the Innokins. The SVD2.0 even uses an Evolve chip. As to toppers, I used the Nautilus' until I started building my own coils and then moved on to Rebuildable Tank Atomizers (RTA). I have noticed that toppers do leak on occasion and some more than others. Laying them on their side, not tight enough, tightening to much, etc. are all culprits for some, but not others. Things aren't perfect for anyone.
At first, I was concerned only for nic replacement, especially since my taste buds were destroyed. Took them a good while to really recover. So I stuck to strong flavors like peppermint.
Being diabetic, I get lab tests quarterly. My doc noticed a slight change and I said that I quit smoking and started vaping. He said, "good". That was it. But my tests have gone up since, too. My dental tech, checking my gums said that they looked much healthier. I didn't tell her why, but I knew why. I notice a lot of other things, too. I am grateful.
I spent $180 a month on cigs, I would spend that to get decent stuff if I had to start all over, even two months worth. It is my health.
Good luck and good health!