I agree completely with this. I have an Evic VT and I enjoyed the temp control, but it's completely unnecessary for me with all my subtanks. I like using all my mods also so it's a pain having nickel coil builds that won't work on other mods.For the price I suppose they're worth the gamble. Personally I'll never buy anything electronic from eleaf, just too flaky for me.
As far as TC goes, I find it kind of pointless for tanks, I just don't get dry hits and they are a non issue for me on them. For RBAs however, I'll occasionally get a hit approaching dry and its annoying, for those I tend to prefer TC builds if the RBA can handle single coils.