El Tesoro (tequila) seems to have moved to synthetic corks. I've already lost a good bottle of another brand's reposado to cork that had dried and flaked in the liquid, so I was eager to see how this one performed.
Essentially, it does the job. No "PHWONK" sound but it creates a tight seal that's easy to remove. I like knowing that it won't/can't flake in the bottle.
Regarding screw caps, I had just opened a Weller Antique 107 for the first time about six weeks ago. I replaced the cap and somehow managed to screw it on so tight that I ruined the cap completely. Not by stripping, but by screwing the top so hard that the top part separated from the sides. Never had that happen before or since.