This is a question that takes me back to my roots. I first started building and repairing bioreactors in 1990. After managing several facilities from 1990 to 2000, I have seen every mistake you can make. The design of the facility and maintenance of the equipment requires unique skills and experience that is not taught in schools. If you have someone that knows how to design, repair and operate bioreactors you should keep it in-house and train everyone well. If not, outsource. It also has nothing to do with budget. I have worked on glass tanks, carbon steel tanks (built in the 60s) and 316L tanks. I even worked at the Pfizer facility that made Penicillin during WWII. If you have experience and skill, you can make good product with any equipment. The best I ever saw was an enzyme facility in South Carolina. The people were trained well and knew how to design, build and repair their own equipment. They also focused on inoculations and transfers. That's where your problems occur most. My other advice is...don't push your density too high. It hurts your purification process, and you will lose any advantage you gained by high density in the reactor.