Let’s put it this way, if a commercial brewery could brew a quality NEIPA or big West Coast in a plastic fermentor or something non pressure rated then they would do so without spending thousands of pounds on pressure vessels.
Going back to my comment, it depends on what you want to achieve. And to answer the original question of this thread, YES, stainless steel is better than plastic and pressure vessels are better than open fermenters for the reasons above.
Let me get comfy whilst I wait for the next plastic bucket user to get upset…
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