I'm actually thinking that they don't last as long. To me, since they stay wet, the filler seems to clog faster than it does when you run it dry and rewet it. My carto has only lasted a little over a week and it actually needed replaced a couple of day ago. I could normally get almost a 2 full weeks out of them before the tank.
For me, the filler doesn't seem to clog more quickly, but it does eventually get clogged and somewhat sticky. I was thinking this was due to running a larger total volume of liquid through it than I normally do without a tank. I've added some vodka (I keep some in a dripper bottle) straight to the carto filler, and that seems to unclog it a little (IME this will force some juice out of the battery end hole). That seems to perk up the wicking some. In my last fills I've just started adding some vodka to the juice before I fill the tank. I'm hoping that will keep the filler from getting as sticky with the larger volume of juice that eventually runs through it in a tank.
I've never gotten two weeks out of a carto before cleaning though, so... I don't know.