good reasons for centralized mass production: controllable standards, centralized waste and production too!
local production: democratic, short transportation, no monoculture, free selection of materials,
Axel Sylvester - 
Access to tools for local people St.Pauli
Reasons for centralized and mass production
* efficiency
* large batches, cheaper production
* theoretically good controllable (industry) standards
* pollution and waste in one place
Local  small
* know how about components and processes
* transparency of production process
* democratic produciton process
* no mono cultural production
* ethical way of production, no exploitation of labour
when is self/local production interesting?
* peak oil scenario
* good for empowerment
* self expression / personal production
* only products that you can directly influence
Interesting reference to Chritsopher Alexander's "Nature of Order" (http://en.wikipedia.org/wiki/The_Nature_of_Order), for a review see http://www.cogsci.umn.edu/colloquia/colloquia_S11/Ritu%20Bhatt_opt.pdf