Action script VS frame by frame animations. Help please

Hi,
I know the frame by frame animations increase the file size. Is frame by frame transitions and movements smoother than scripted ones (AS) ?
I have seen they usually use frame by frame animations in those proffesional and costly ($60 to $100) flash templates with smooth and fast transitions and movements.
I use AS myself even for small movements.
Any suggestions? Experience on this?

Thanks.