Not true at all.
Halo uses 808 threading. There are a LOT of 808 threaded parts from different manufacturers. It's far from exclusive to Halo.
Personally, I have trouble recommending anything with 510 threading. I know it's the most common, but it's also where all of the crappy junk is around. Come here any time day or night and I can assure you on the first page there will be a thread about leaking clearos, failed batteries, two parts that don't work together because of poor fit, or other broken parts and it will ALWAYS be 510 threaded parts being discussed.
Another problem with 510 threading is it's fragile. You'll never hear someone say "I broke the threads on my Triton when I accidentally dropped it." 510 threading though...
http://www.e-cigarette-forum.com/fo...kanger-protank-threads-snapped-clean-off.html
Halo stuff is among if not THE best. Out of 7 clearomizers I have never had one leak a drop, and never had one fail or need to be replaced. Name me a 510 threaded clearo that never ever leaks. I can lay flat on my back, hold my Triton upside-down, and use it without any gurgling or liquid leaking into the drip tip. Try that with your average Ego and see what happens. And then there are the batteries, which frankly Halo batteries blow Egos out of the water. I've got a Joyetech Ego and a Halo Triton, and my 650 mAh Halo battery lasts longer than my 1000 mAh Ego.
Oh no, you can't put lots of different 3rd party parts on the Halo...
But why would you want to when the Halo parts outperform 99% of the 510 threaded junk?