The slot inside Madvapes' VV Boxes containing the electronics is encased in hot glue. (I should know; I own seven of them...)
5V regulated boxes look similar, since they all use plastic 3AA battery boxes as cases. They differ in the particular regulator chip/board used, the power rating of the switch, and the placement of the connector/switch/internal board (using either the center slot or the slot on the right side). I currently own four 5V boxes---a Big Kazoo from KalamazooVaporShop, a 5V box from GoodEJuice (which they no longer sell), and two 5V boxes from MaximumVapors (with two more on order).
Todd at MaximumVapors is very meticulous. While he doesn't encase internal components in hot glue, his builds are very clean and solid. The boards are screwed down, the solder joints are strong, and his wiring is efficient (wires are exactly the right length). He also uses drip wells on his 510 connectors, which is a nice touch. Regular price for his 5V boxes is a steal---$20 shipped. His 5V boards are rated at 3 amps with 5A-rated switches (horn buttons).
MaximumVapors 5V boxes work beautifully with the cartos I use most---SmokTech 1.7 ohm Resurrectors and 1.6 ohm dual coils, and Boges (both LR and SR)---either alone or in carto tanks. I wouldn't use any of the various updates of CE2s with them (the only ones I use are Micromizer X7s), because MicroCigs' fillerless cartos are not designed for high voltage. Also, some juices can't handle the heat and lose flavor at 5 volts.