V4L cartos are made by manufacturers that also supply other retailers like Vapornine and Cigeasy. Vapornines "Turbos" are the same as V4L's "Cool Carts". I'm not sure whether Cigeasy's "Gold Label" carts are are the same as V4L's "Cool Carts" or the "Premiums".
As far as Cool Carts vs Premiums - they are both kind of like Low Resistance versions of the old standard KR808D-1 - they vaporize more juice faster to produce a more vapor and a bigger hit at whatever voltage you are using than a standard carto would. I haven't noticed that they hold more juice, but they definitely go through the juice faster because, well, more juice is getting vaporized. If your use them you should be familiar with refilling and keeping the cartos wet.
I really like them both. My opinion: The Cool Carts, because they run cooler, are awesome at higher voltages because they are less prone to heating up. The Premiums, IMO, produce a bit more vapor at lower voltages, and at higher voltage sometimes a big warm hit is just what the doctor ordered. I actually use both at 4.5 to 5 volts.