It depends a lot on the brand. For cheap ones like Rokinon, they are the same other than being 'clickless' (no stops on the aperture ring), T-stops (transmission rather than F-stops) and having a geared focus ring for easy use with follow focus rigs.
Better lenses (top end Zeiss, Schneider etc.) are very closely matched between samples in terms of colour transmission, contrast etc. since one crew's footage and another's shot with different copies needs to match up or one rental copy to the next needs to look the same. This is probably the biggest reason for the often huge cost difference. The best cine lenses also have minimal change in focal length when focused so that when racking focus in footage the image doesn't get smaller/larger which is very distracting - another consideration ignored in stills lens designs.
For stills use lenses for stills and save yourself lots of money! Cine lenses may be amazingly consistent copy-to-copy but that doesn't mean they are amazing performers by stills standards, 1080p is only 2MP.
