I like my ego-T type B. The actual tanks themselves and the T atty really do a great job of muting flavor, i won't argue with that. But on the other hand, the kit makes a fantastic starting point. The batteries with the lockout feature are great, I wouldn't want a plastic clip that covers the button to rely on while it's in my pocket. The tanks do hold a lot of liquid which is nice for when you don't have time to fiddle with cartos and the like, while driving is a great example. The wide mouthpiece feels good too.. and despite muting flavors (some still come through well), it does produce thick clouds of vapor. Notably cooler vapor than cartos too, but the T attys are a bit fiddly. One of mine leaked out of the box, but a wick adjustment solved it.
Between the tanks and some Boge 2.0 Ohm cartos, I have a pretty good all encompassing setup. I like the tanks too for trying out new liquids without dripping, you don't get the media inside the carto soaked with a juice you don't like that's hard to get out. Just pop a new tank on and take a few drags - voila, new flavor. I have a few drip tips as well that I use for the cartos - the rubber mouthpieces that they come with tend to condense and collect the vapor which contributes to juice in your mouth. I just pop the rubber ends off and throw them away. The drip tip also makes refilling a breeze.
The regular 650 batteries that come with the kit last me almost all day with the LRs and they'll recharge in about 2 hours plugged into the USB port on my desktop pc. Everyone I know with a regular 510 is jealous of my setup.. makes the regular 510s seem weak. I've had my ego almost 2 months now and the batteries still perform as if they were new. I just ordered a 900mAH battery two days ago to experiment with, hopefully it isn't too huge. The 650s are a good balance of portability and longevity, imo. Oh, and the different size batteries will all perform the exact same way - the larger ones will just have a longer and more consistent run time.
I'm happy with my setup for now, doesn't make me itch for a mod or anything quite yet. The whole 510 platform is pretty expansive so you have a lot of options. I chose the T mainly because you get the T stuff for cheaper buying it as a kit, and the lockout on the batteries was a huge selling point too.
HTH.