The kr808 and the 901 used to be my favorites. When I first got my 510, I loved
vaping it, but the constant topping off to avoid the burnt taste when heavy
vaping was a real drag. Then I tried this:
Cart Mod for better refilling
I use a coffee stirrer. Not only does it eliminate the topping off, the draw and vapor are improved. I do not trim the bottom of the poly, just a little off the side. If the cart won't take much liquid, you haven't trimmed enough. If it sounds like a slurpee and floods the atty, you trimmed too much.
Takes some experimenting to get it right, but once you do it will make a huge difference
You can get whistle tips to fit 'em or squeeze a 901 cart in (they break in after a few times) but I prefer the round ones anyway.
The batt life
is shorter, but with a few spares and a PCC it's not an issue for me, though I may get a passthrough for sitting at the computer. And yeah, the 510 is still a juice hog but that's the price you pay for clouds o' vapor and great throat hit!
Also the 510 seems to be much better for dripping which I love to do when switching between flavors.