I have both tanks the OP is preferring to. The MadVapes tank is a lot bigger and holds more juice. It's also sharper looking than mom and pops tank.
But Mom and pops tank does have it's advantages. I have the big (5ml) sub tank. And this tank can be used on a cartomizer that wouldn't normally be used with a tank, like the boge cartomizers.
The Mad Vapes tank is longer and you would have to find a cartomizer thats long enough to fit. The Smoketech carto's are made to be used with this tank. And if you want to use other carto's then you would need to use one thats at least 45mm's long, not counting the threaded part that screws into your mod.
The mom and pops 5 ml sub tank I have measures about 37mm's long, or maybe 38mm's long...it's hard to tell with my tape measure.