This is a bit complicated because the issues involve different parts of the device.
leakage and burning are atty related whereas charge time is specific to internal battery mods.
leakage is usually by far the biggest one. An atty that leaks both wastes expensive juice and causes serious problems to everything it is stored along side. It can ruin clothing, cause failures in other even more expensive things like cell phones stored in the same pocket, etc.
burnt attys would be the next problem. All wicks eventually burn, but the time they take to become unusable is directly related to cost and convenience. A cartridge that burns immediately is a useless wasted cartridge, and another spare might not be on hand. A cartridge that burns twice as fast as another effectively costs twice as much because less use can be gotten out of it. It also requires twice as much maintenance because it needs to be changed twice as often.
charge time is one I personally avoid by using replacable batteries.