Beware - Company is Slow and Revisions Are Likely

I am in the middle of clear correct braces. I needed a significant revision mid-process as my teeth did not shift as intended. This meant my dentist had to take new impressions and the company has to make new braces. It has taken the company 6 weeks to make the revised set (assuming they come in when promised.) It is incredibly frustrating to lose so much time. Meanwhile, I am wearing my last set as retainers, which are now disgusting as they are not intended for long-term wear. They are grungy and browned - unwearable in public. My dentist did not tell me that approximately 40 - 50% of his patients need revisions mid-process. Not sure I would undertake the process again, and I would definitely chose Invisaligners instead.