Hardly anyone continues to use the atomizer+cartridge on the normal Ego. Most people switch to cartomizers for their everyday
vaping, and atomizer+drip tip at home for testing juices and occasional juices. The most popular cartos on 450mah+ 510 threaded deices are are Boge 510 2 ohm.
The Ego-T uses plastic tanks on more expensive atomizers that are different inside and have a spike to puncture the tank. Some have trouble with leaks or burnt taste (same could be said of atomizer+cartridge or new carto users). At least 50% of the people who start with the -T switch to cartomizers. One nice point is the 5-click enable/disable batteries - safer to pocket.
IMO whichever you get I recommend getting some cartomizers as a backup and for clingy flavors you don't want in your atomizers.