i'm guessing that i would be better off filling my own? that definitely does make some sense. haha.
Yup, by far. I've had pre-filled cartos that were "ok," but I've never had one that I actually wanted to vape, if given the option. And even the ones that taste great can be subject to quality and consistency control issues, like what you've probably just experienced.
Filling them yourself Is a hell of a lot cheaper, and you can put whatever you want in them obviously, so you know exactly what you did, so if something tastes or feels wrong, you can learn from that, rather than having to take a wild guess at what the guy in the factory might have done wrong while filling your carto.
Although, in my experience, pre-filled cartos do go a little longer before they need refilling for me. But I think that's mostly because I don't let me cartos sit when I fill them - just fill and vape! With pre-filled's, they sit around for a while, soaking evenly. I think that's all it probably is.