My atomizer that leaks when it hits 1/4 tank or less, leaks with new tanks punctured empty and filled 3/4 with a syringe. Cap never off it. It leaks with 80/20 up to 50/50
My non leaking atomizer doesn't leak no matter which tank I put on it, used on a different atty, cap taken off dozen of times and refilled and juice from 80/20 to 50/50. 50/50 needs a few more priming pumps, but that's it.
My unsolicited advise after 3 1/2 days fiddling with my two problem eGo-T attys and one good one,
1) If you are getting tons of vapor and little flavor, don't mess with it. You are getting the right amount of juice wicking down. Just keep vaping all your least favorite juices (can't taste them anyway) or menthol. Menthol/Mint is one of the few flavors that comes through. Eventually the atomizer will hopefully break in and flavor will improve. It hasn't happened for me yet, but I am hopeful.
2) If you are getting leaks or bad air flow/burning, make sure the flat edges of the tank line up with the flat edges of the piercing plate so air can come through. If you block them with the rounded side, it doesn't take much for the suction to take the path of least resistance up the short end of the needle side of the tank and give you a mouthful of juice. The needles should really be longer on these since the short side is lower than the built in plastic gasket. I'd rather a tank didn't totally drain than get leaks. If the tank/plate don't connect exactly parallel, it doesn't take much for it to leak out on the plate no matter how careful you are. These plastic tanks don't seem precise enough and 1mm can make a huge difference. If these needles are hand cut and slightly different lengths, that could be why some atomizers are leak prone to different degrees.
3) Wicks - These are definitely hand done and prone to different densities and locations. Too loose or too low and it drips too fast, stuffed tight and or high and it won't wick well. There are three grooves in the needle tube and a thin ring of mesh holding the wick bundle together that probably help it a long a bit, but the mesh is not wide enough to cover the entire distance down the needle, at least on mine. I wouldn't vape any juice that has sediment (coffees, sweet thick VG) because as it all travels down the wick stuffed 1/8 needle tube, it could easily clog up the mesh/wicks/grooves. All juice travels down through that wick filter. If it does clog shaking warm water or vodka in a tank would probably clean off the top of the wick without soaking the entire atomizer.
I so want to love my eGo-T but even my good one with good vapor still has little taste and I don't like menthol very much. All my delicious BWB's flavors are a waste in these, so I am back to my KR808D1 Boge/Coolcarts on my 5V passthru for those and will occasionally keep puffing on my eGo-T at home making clouds with my least favorites hoping the atomizer finally breaks in and reminds me why I didn't like them. Good flavor is my most important vaping element.
When my sillca rope comes I'll try to build a wick that hopefully fixes the leaking and improves the flavor.
Otherwise I'll patiently wait for Version 3 atomizers.
By the way I also bought my kit and spare atty at Cignot, so I don't think one vendor has better product that the others. The good one was one in the kit. I think it is the luck of the draw whether you get a prefect wick/needle/shaped one or not and the wick can move with vigorous washing, blowing, puncturing which could change the equation at any time.
Haping vaping and I hope everyone else gets perfect ones.
The one thing that Scott mentions though is crucial, imo. For one thing the outside wall of the atty can vary so slightly and if it is a tight fit you have a pressure going where the only outlet may push that wick or even open up a 'channel' next to it where juice could flow too easily. Other attys might be slightly above spec and no pressure system created. Then if you're filling from the cap and not puncturing first, that is only going to exacerbate the situation. 
). Hope this information was helpful. 
