You are looking for something to put on your Ego and want to know the best ohm range for the topper?
If so, somewhere around 2.0 in my opinion. I wouldn't go much lower than maybe 1.8 or much higher than 2.2 or 2.4. Lower ohms will produce a higher wattage on the basic Ego, and more vapor and flavor typically. They will also drain the battery charge faster, and most Ego manufacturers don't recommend going below 2.0 ohms. Just one persons opinion though.
The Evod clone is decent, and it comes in around 2.4 ohms. But it is not recommended with tank cracker juices. The DCT pyrex carto tank will handle tank crackers, but then you need to buy carto's for it.
Edit, above poster is correct, higher ohms will drain the battery slower than lower ohms.