ExtremeDooty, Vaporesso make some good products. I got a Switcher after a horrible experience with a SMOK Procolour, the SMOK just burnt through coils as fast as you could install them.
Started to use GT CCell coils, nice clean vape and last for a decent amount of time, upgraded from the NRG tank to Cascade due to larger capacity. Also found it to give good flavour, when it didn't leak.
Recently picked up a Luxe with 8ml Skrr tank and so far enjoying it, apart from GT CCell's don't seem to work well with Bad Drip liquid. Gunked up the coils and gave a lovely acrid burnt taste to the vape experience. Note to self, do not buy or use Bad Drip with GT CCell's.
I just mentioned Smoant as an alternative as they are reliable and have a following, due to how they perform. Plus they're cheaper than a lot of other brands, so you can get a lot for your money.