A regulated battery is going to be preferable for most, because varying voltage output from the battery changes the flavor, TH, vapor amount, etc with the vaping experience. It may be a big deal for some, and not so big for others.
When the battery is at full charge just off the charger, it's going to put out say 4.2V. As you use it through the day, it will drop as you use it. The second time you use it it may be at 3.9V. The 5th time you use it it may be at 3.6V. And it will stay at the nominal voltage for a bit then start dropping again. By now you are getting less vapor, TH, and flavor. You might elect to throw it back on the charger at this point, but that's really not a good idea. You need to wait until the battery signals that it needs a charge - most will flash the LED. The battery needs to be used to it's minimum voltage, then recharged just like many other lithium rechargeables.
With a regulated battery, it stays at one voltage the whole time it's being used. This creates the same experience each time without dropping voltages and loosing all of the good stuff that comes with vaping. The battery will need to be charged more frequently in this case.