Quite a good tank. Paired it with a Procolor for a couple of years (which survived my driving a Land Rover over it to be fair to Smok). Main drawbacks are that it almost always leaks a bit, and the coils are abysmal if you stick to their brand. Vaporesso GT coils (for the NRG) sorted it the best for coil longevity and stopping so many leaks down through the air-inlet holes. It's a 5ml with the adaptor (I'm in the EU TPD rules zone), and filling is easy. Overall I like the tank, I like the ease of use, I don't like the incessant leaking from the lid seal. It probably deserves a score of 3/5 but I'll give it 4 for its ease of use and huge cross-compatibility (a lot of different coils fit and also work in it).