To my long experience ISO 9001 only assures consistency in you products therefore, if your work is good all products will be good. However, if you do a lousy job all your products will the same. ISO 9001 forces you to work to strict and fixed documented design and development procedures, work and test procedures. However, the catch is that you and only your professional are the people who writes the documents and procedures. No one else know better what you design how you design and make. Therefore, if your company workers are professionals, committed and caring, the design and and products quality will be OK. However, if your company doesn't value professionals and experienced staff but see everything in Dollars through shortcuts in the R&D, design and testing in the development process (which is very easy to save by cutting corners, less prototypes, less design iterations, less time for the professionals to think, analyse, research, etc.,) then your ISO 9001 will be your downfall.