[dyscrete]

Would this be a bad thing in the scenario one browser didn't implement the property properly? The webkit implementation could work fine but look awful on IE for example, which then you would simply not include it in IE.

[treve]

Not really, because the features need to be explicitly enabled. Nobody will use these in production if it requires a user to change a setting in their browser for it to work.

[Raticide]

Potentially yes, this is why prefixes were created. But in practice I haven't run into any issues like this since the IE6 days.