I like the cone with 901 lr and without with 510 lr
I preffer the cone on.
1) the atomizer can get warm. The cone stands between my finger and it.
2) If i over fill my cart, the cone stands between me and ejuice on my hands/in pocket
3) asthetic
There is a harder pull on the device while it is on though. I have been giving some decent amount of thought to just drilling a hole in the cone. I dont know, maybe one or two 1/16th or 1/32nd diameter holes will do well to decrease the resistance on my pulls.
The main thing the cone does (which makes it worth while) is to keep any liquid leakage contained. That is HUGE! ...plus I do think it makes for a tighter draw (which many prefer - myself included).
Cone on is better for me. Although I cant use it with my LR 306s so I might just go back to LR510
Stu just buy a 901 cone and your good to go buddy