It's easy to get consistent results with the right environment. Just have to repeat what works, and keep everything sterile between grows. I like new air stones and hydroten. Long as you keep the nutes simple, not a lot of additives. It's no different then any other way of growing except keeping the rootzone cool. If you can keep the res temps under 70 you should be fine, and if you can't just run
hydroguard and you'll keep prefect roots.
People make dwc out to be something hard, for me it's set it and forget it. Just watch ph and the plant and it'll tell you what ever you need to know.
To get consistent results all you have to do is keep consistent practices.