So what's the difference between XLIM V2 and XLIM SE?

XLIM V2 and XLIM SE use the same V2 pod catridges, they also have same airflow ring on the side, they basically have the same performance in terms of battery life and flavor.

XLIM V2 has a OLED screen to display the basic information like wattage, resistance, puff counter and battery life, and it has a button to vape or adjust the wattage, so the XLIM V2 is both button activated and draw activated. XLIM SE has no screen and no button, so you cannot adjust the wattage. 

In a word, XLIM SE is very simple and very friendly for beginners while XLIM V2 has more features like adjusting wattage. But they are the same in terms of performance.