The lower the ohm the more power required and bigger clouds. The higher the ohm the less power and more flavor. Everyone is different so I would recommend trying different ohms/wattage until you get where you want to be. I usually like to be around 0.4-0.6 and around 40-50 watts but thats just me.it might be a stupid question but what the difference in 0.25 and 0.5 ohm? i mean, lower resistance like 0.2;0.3 and higher like 0.5 or 1 ohm?