Both will work fine. A carto tank is just that, a tank that holds a carto -- if the carto fits, it'll work, unless your PV has a really deep drip well, then you would need an extender adapter.
For tanks you want to use stainless steel (bare) cartos, and they need to be punched (round hole) or slotted -- the punch or slot is what feeds the eliquid into the carto, to keep it wet. You can buy prepunched cartos from multiple vendors, though most of us slot or or punch our own fairly quickly. I use a DIY punch I posted in the PIF area, COV sells a nice one for $15, you can use a 1/4" self-piercing saddle valve from the plumbing section of a hardware store, or a dremel tube-cutter wheel to slot. Personally I found saddle valve cumbersome, a PITA, but it absolutely does work. I used a dremel until I came up with my DIY punch.
The only tank I've owned is the notcigs M1A1. It's been a real workhorse, after 7 months of every day, 6 + ml/day, use, I'm only now needing to replace one o-ring on it.
Carto replacement on the tank I use, and most others that I've heard of, is pretty simple. Tanks have top and bottom end caps, with o-rings that the carto slides through to seal them. Just lube the o-rings with a little eliquid and slide the carto into the bottom (a slight twisting motion helps get it past the o-ring, compresses it instead of shearing).
I top fill -- with the carto top below the top cap, tank at an angle, squeeze eliquid out of a bottle into the gap, then slide the carto the rest of the way up, again use a slight twisting motion.
On first fill, prime the carto -- drip some liquid into the top of it, to moisten the filler top. When you first insert the carto all the way, the holes or slots should be just above the bottom cap, and you should see a little bubbling -- that's the liquid going into the carto. Give it a minute or two for the original soaking, blow through it onto a tissue to clear any excess (same as for just using a carto by itslef), and you're set to go. You shouldn't worry about priming the top after the initial setup, even if it looks dry.
Tanks don't magically extend the life of cartos, but do keep the fiddle factor down -- you'll top off a tank much less often than just a carto. I ran 22 - 24 ml of eliquid through plain cartos, get the same amount through when using a tank, before it's time to toss them or clean them.
