The first few days were absolute torture even without the attachments, but with time, ibuprofen, and a small nail file I was able to get used to them. I now file the edges of the trays and take some ibuprofen before popping them in at bedtime. I had a couple more days of torture six weeks in when I got my attachments. As with the first trays, time and ibuprofen helped and now I only experience mild discomfort with every new tray.
I don't need any special tools to pop them out for cleaning; I just dig a fingernail into the back of each tray and peel it out. I try not to have them out for more than 2 hours a day, but when dining out it's usually longer than that. I don't think it's affected movement overall, but the trays feel much tighter when I pop them back in.
For cleaning, I started out using Retainer Brite in a glass of warm water then brushing vigorously to get out the gunk. I was still seeing some yellowing so I switched to a small ultrasonic cleaner (around $24 on Amazon) which made the Retainer Brite much more effective & completely eliminated the need for scrubbing! I run the cleaner for around 15 minutes during dinner every night and they look almost as good as new at the end of 2 weeks.
My one and only complaint about the product is occasional peeling. I don't know if it's my bite or a defect, but I've had 3 trays on which a thin layer of plastic coating began to peel off after a week. It didn't affect quality but was intensely annoying, like having a huge chunk of food stuck in my front teeth. I'm more careful now to avoid clenching or grinding, but after 24 hours of continuous wear the trays get annoying and I tend to 'chew' on them, chomping down like I have gum in my mouth.