Classic Pen Style is the first generation electronic cigarette that started the industry. Although this particular model is fairly large in size, it is heavily preferred among many veteran e-smokers due to it's exceptional value. The Classic Pen Style is loaded with a big four-hole atomizer to give you an extremely easy draw, a long-lasting battery, and a super big cartridge that holds at least 15+ drops of liquid. 
We certainly recommend the Classic Pen Style if you are looking for the smoothest inahalation possible, combined with stamina and performance.

Pros: Easy draw, easy cartidge refilling, and great all-around performance.

Cons: Big form factor.

Overall: If you don't mind the big size, this model is the best bang for your buck.