I have two vacuum fillers: a Pilot Custom 823 and a TWSBI Vac 700R.
Two very different pens in terms of looks and price classes. The TWSBI is usually between $65-$85 and the Pilot usually between $300-$350. And the price class is important to keep in mind when I say what I’m going to say. And it isn’t a knock against TWSBI, but rather an observation of the differences in quality with more expensive pens.
What I have noticed when I’m getting really close to writing these pens dry, is that the Pilot just writes as expected until fully dry. But the TWSBI will often start to bubble and just push out a bunch of inks as it is getting really close to empty.
It is good to know, so you don’t end up with a bunch of pink ink on the page in the middle of a meeting.