I bought a couple eGo-T batteries at my local shop recently. Is that what you guys are talking about? I suspect you're talking about something a bit more powerful and sophisticated.
Yes, the Ego-T batteries are what people are talking about when they just say their next step was an Ego. I've still got a bunch of them in 400mAh (my very favorite battery for stealth vaping), 650mAh, 900mAh, and the 1100mAh. I can't seem to "kill" any of them, except for stripping the 510 threads needed for charging them. Got that solved though, with the adapter I found and use on the stripped ones. It's an eGo to Ego/510, and Kidney Punch and Ecigarette Impressions used to be the only places that had them. They're about $2.95-$4.00 a piece.
The eGos were my next step after my JoyeTech 510 kit. Used the same little Vision Nano Clearos on them...that I'd gone to for the JoyeTech 510 kit. Then discovered the Innokin iClear 16D clearos, too. I still use them daily, along with PT, Aerotank, and other tanks. Have also gone to iStick, Eleaf, Sigelei, Provari, and Kanger mods. But...sometimes I just need to vape with some old school stuff, too.
By the way, Mike...if you like those eGo batteries...you can get them cheap at LaserLiquids. Good company, great prices, and customer service. I buy them there to have on hand for "newbies" I'm helping to switch to vaping.