Before you get into the rba's, you might want to give the Kanger T3's a try. They only hold about 3ml but they are a great vape compared to a carto tank. The world of rba's is very large and sometimes hard to get a complete grip of without trial and error. Some are easier than others to use. Most look really out of place on an ego battery though. The T3's are the same size as the ego batts, so they look nice also.