It all comes down to Ohm's Law. Dont worry, this is basic algebra.
V = IR
V = voltage
A standard ego battery is 3.2 Volts
I = Current
Its how many coulumbs per second passes through the circuit. How much charge per second. It is measured in Amps.
R = Resistance
This name is rather acurate. It is a measure of how much the circuit is resisting current flow.
Your battery is going to remain constant because you are not going to change it until it is, or close to, dead. But you will change the resistance of your atomizer. If you lower the resistance, you will need to increase the current flowing through the circuit. If you dont, then you will be violating Ohm's Law. The quicker you draw current out of the battery, the faster it will go dead.
Also, since more current will be passing through the low resistance atomizer/cartomizer it is not uncommon for them to go dead faster. The action of current passing through the resistance in the circuit generates heat. The more current, the more heat. It just burns itself out quicker. But, most like the flavor and vapor production much more with the low resistance atomizers/cartomizers than with the normal ones..
With a standard battery and atomizer you are looking at something like 6 hours of use. With a low resistance atomizer you will cause your battery to go dead faster. So, the long and short of it is that youll want to carry an extra battery with you. If you are like me, and you're paranoid of your battery going dead... youll be carrying an extra one anyways.
So, if you mormally carry an extra battery with you, you'll see little to no differance in your daily routine. But, most say they enjoy the quality of vaping with a low resistance atomizer better than vaping off a normal atomizer.
As for the debate about atomizers vs cartomizers... well lets just say that this topic has gone on for dozens of pages in other threads. Each person has thier own favorites, for their own reasons. The only way youre going to know which you prefer is if you try them yourself.
