I used Plastruct's liquid for a long time till I knocked that skinny B over months back :'(
Been using that Testors red label since ---what they had when I went for more . no complaints.
I remember the Plastruct being a bit more viscous but ? , not too sure now. Picked up one of the Testors Cement Pens to check it out . Like it . You can knife the felt applicator tip to a point or whatever you like .
It's more for larger joints though , even with the felt whittled down.
CA of course ,,,,,,,,,,,I like to rub it between the tip of my thumb and index finger with a good healthy pinch of baking soda .