I have been on 8 ABDs with my kids and we have had some amazing trips together. We also experienced one pretty awful other guests (but she was bad enough that it made a lasting impression) and had some negative experiences with
ABD (which I've detailed here). I would say that the good have far out-weighed the bad, but I did not like how ABD managed their operations during COVID (I had a trip booked so can speak from first-hand knowledge). I would not rule out taking another ABD, especially to places where I would not feel comfortable traveling solo, such as Morocco, Egypt and India, but I will also be looking at other providers when the time comes (one of them will be Backroads because I really enjoy active vacations).
FTR I've only traveled with one other tour company, A&K Family, (albeit on a cruise to Antarctica) and the ABD guides were superior in every respect to A&K.
I travel solo a lot now and much prefer being on my own. I like staying in places a bit longer (some ABDs have a lot of packing up and changing hotels, mind you it's because you see *so* much with them) and not being tied to a schedule.
I will say that there is no way I would have done China on our own. The language barrier, especially in Beijing, was insurmountable, not to mention the travel between places, especially by plane, where staff at the airports and on the planes for the most part didn't speak a word of English. I have good friends that organized a private tour with guides and airport transfers organized for each city, but they speak Cantonese and understand Mandarin, which made a difference for them. I'm not sure if they saved any money versus going on a tour, but it is something to think about because you tailor the schedule to do exactly how much or little you want.