The two models you are considering are excellent choices and far more effective than your current e-cig.
There really is no conflict between the eGO (aka Tornado) and the Joye 510. They are both made by JoyeTech and use the Joye 510 atomizer ... and generate excellent vapor. [I am one of the few people who doesn't get much TH from the 510 atty; most people are impressed with the 510's TH.]
The difference is the size and capacity of the battery (and the price). The Joye 510 battery is 180 mAh (milliamp hours); the eGO is 650 mAh. The greater the mAh, the more puffs between battery recharges. So the eGO will go for about 3 1/2 longer before needing to be recharged ... and you pay for it.
The eGO kit (~$80) is twice the cost of the Joye 510 kit (~$40). However, you probably would want to supplement the 510 with a $25 PCC (personal charging case, to charge your second battery while you are out and about) and/or an extra battery in order to sustain you throughout the day. So, effectively, there is not that much difference in price.
They look and feel different. The eGO is bigger and a bit heavier. If you prefer the look and feel of one over the other, choose that one. Otherwise, I would go with the eGO (or Tornado).