I've used the GS Ni coils and nothing else so far, it's just the airflow feels a little too restricted and I'm drawing a little too hard on it to get a decent sized cloud. What do you use now?
Don't get me wrong it's a great mod. I bought it after my wismec press VV gave up the ghost.
I started with the iStick tc40 with a nautilus mini, then moved on to the kanger subtank mini, which is where my first tinkering with TC coils began, it's much airier than the gs tank I believe (have the gs-mini, but seldom use it), and the subtank mini rba was the starting point from where I started making my own coils. It's one I wood still highly recommend, especially if you find the draw on the gs too restricted. It has a newer version, the toptank mini, which is just as good although the top fill is a bit leaky (can be remedied by sliding a Vape band over the airflow when you refill)
Now I have a number of mods - the evic vtc mini would be a good progression if you get to the point where you find the battery life or the power of the iStick is not cutting it for you. I also have the wismec presa 75tc, which is lovely, if you liked the wismec presa you had. I also have the cuboid (dual battery big daddy of the evic vtc) and the iStick 100tc. However, I tend to have my mods on around 50-60w, and temperature around 450f.
Tanks, I build my own coils, mostly in nife30 these days, always a velocity style deck as easiest to build on, and tanks I use are: crius, aromamizer, smok rdta. They are all very flavoursome tanks that can produce big billowy clouds, although I am more interested in the flavour.
What I like about TC is that the battery life of my mods seems to go much further, and the coils stay cleaner for longer, and I seldom experience a dry hit, although admittedly there is a learning curve with TC. Once you get it running nicely it's lovely. Just a lot of people give up before getting to that point.