Welcome to ECF!!
Carts are used with 3 part PV's (batt, atty, cart) and have just a mouth piece and the filler material you load up with
juice.
Cartos are used with 2 part PV's (batt, carto) and have the mouth piece, filler AND atty all in one. Pretty nice and convenient when you don't want to fuss with refilling and/or topping off.
Really a matter of taste/style IMHO. I've been a 801/cart user for over a year now and just tried the TW 510 Mega Cartos and have been pretty impressed. Now I'm still learning and goofing up the refilling trick with these as it is a pretty small hole to work with and I don't have a syringe to help but otherwise, it's a pretty nice change.
Hope this helps. Search/read/search/read here and wait a few more minutes for oh.....5-10 more responses
