adhesive are better, the in track ones can fall out or get loose, they also jam the window when it is rolled up into the track cause they take up space that was meant for only the window to be there, that in turn puts strain on power window motors. another problem is that will put pressure on window tint that is applied to the glass which over time will cause it to push on the tint and make it shift or peel. lastly if you look at someones car that has them look at the top edge of the window rolled down, they start to scratch the glass along the top edge which looks bad if you like to ride around with your windows rolled half way down