I like how much more flavor I get out of a carto. I have tried stardusts and it wasn't much better then what I was getting from my ego-c at the time. When I used my first caro it was a WOW moment for me. The cartos hold about 1ml of juice in them. You can use them with out a tank but it would need to be topped off regularly to keep it from running dry. Adding a tank allows for a all day vape sitch with out need to top off.
Cons:
can be messy to fill, some methods are messier than others.
Can't chain vape, the carto needs a few seconds after each vape to rewick, depending on how large/long you draws are.
Bit of a learning curve when punching: how many holes you need, flooding, and dry hits. But once you get it, it's hits s'all good.
For me it was worth it. I caught on quickly. I tried different cartos to find my fav's. I have some cheaper tanks from starting off and one Pyrex ValleyViewVapes tank (I got a side fill hole, I don't care for it. The screw has come out twice in my pocket dumping my juice. Others complain they lose the screw.) I have a list of tanks I want to get next, pretty end caps, glass designs, even a blown glass one.
I really enjoy my carto tanks but there are many that hate them. Seems they run about 50/50 carto tank vs. ViVi Nova's. Seems if you like stadust those ppl tend to go with Vivi's, but i don't thing they offer a pyrex glass tank. I could be wrong. If you want to try carto's I'd suggest getting a few and try them without a tank and see if you like them. If you have a local vape shop near buy they may let you try one. Shrug.
Moral of the story, you'll never know if you'll like it till you try it.
Happy Vaping!!