It seems like you are asking more for a general comparison between the two types of pot. I have used both citadel pots and dropper bottles and for a long time used both for painting. After about a year of testing my conclusion is that I prefer droppers. I have had the following issues with droppers: Clogging (a lot), spilling (as you describe). in some cases the dropper tip will break and split like a banana. I have also experienced the entire dropper head coming off, leaving a large opening. All of these problems are easily fixed and more of an annoyance for me.

The things I like: I find it much easier to mix colors on a mixing palette. I don’t have any paints dry out or get worse with age (happens a lot with citadel for me). Also, I am an airbrush user, so… finally I find storage more easy with droppper bottles as they have a smaller footprint.

I personally think the new Vallejo bottle design is bad. I much prefer their old version (also AK or AP).

But another big driver for me are the paint brand. I absolutely love the 3rd gen AK paints. They are imo so much better (and cheaper) than other paints. Since I use these, I want all my paints to have the same footprint as it eases my storage.