Just got my first two mods about a week ago (silver bullet and BB), and got a 3.5 ml Smoktech DCT to try out with Mrs.T's Bakery's amoretta coffee with whipped cream juice. So far, no issues. Easy to fill, great juice flavor and plume, no leakage, and is portable enough to bring with me anywhere.
Yesterday I ordered 4 more DCT but with the polypropylene tubes.
Accessories - PBDragon.com
I prefer the polypropylene over polycarbonate because I believe it is a stronger, more rugged material and resists degradation when in contact with certain aggressive juices.
I ordered a red, clear, blue, and yellow with color-matched Ming/Pawn drips tips. The different colored tanks will each get one of my favorite juices, and allow easy recognition. Red gets the Copper Creek's house blend, yellow gets Volcanocigs' Premium USA V-Liquid - pele's papaya, clear gets the Virgin Vapor's kona coffee velvet milkshake, and blue gets my standby Smokeless Image ice menthol.
I found that you can store/carry up to 4 of the smaller tanks with drip tips in the little clear plastic containers that Q-Tips come in. Just line the box with a thin layer of flat foam.