Ok, so with the Cartotank (from IBT).
1) They offer anodized Aluminum or Stainless steel caps...other than looks does this make a difference?
2) The refilling drip tip, how much faff does this actually save?
3) Other than the carto's they sell at IBT what are generally considered the most reliable cartos for a tank? I'd hope for an XL tank but could cope if it was regular or halfling.
1) Other than looks there is no difference.
2) The refilling drip tip is worth the small cost. I have found it makes it easier to get carto's lined back up when you are putting them in the tank, or refiling. I have only one tank that is not an IBT, and it is a tight fit to get the carto past the top cap and its o-ring, the tolerances aren't as good as the IBT's, and I often pop the top or bottom cap off trying to force it without the refiling drip tip. Never have that experince with the IBT's, better build quality, or maybe tighter seal between the caps and the tube?
3) This comes down to personal taste and budget. I like IKENVape Carto's the best. I like the 510 platinum carto's that have no flange. These aren't as readily available and have a slightly higher cost, but I think they are the superior product, and I get the longest life out of them. I can refill a tank many times over before I have to swap in a new carto.
When you order get a few extra thingies, they are the little plastic pill bottles that the tank ships in.