Yes and no. Phobio is their trade-in partner. I have done a mail-in trade-in with them and yes the criticisms are legit. I don't know if their practices have changed or if Apple made them do things differently but it has seemed to get better. Years ago I remember trying to trade in a MBP and they gave me a much lower quote when they received the device. I kept it and later sold it on Swappa for a much better price than Apple/Phobio.
This year when I traded in my Imac for the Studio (with Apple/Phobio) I was afraid the same thing was going to happen but it did not. They gave me the quoted price.
I know I've heard conflicting stories about whether Apple accepts in-store trade-ins for devices other than iPhones. When I've traded in iPhones at my local store - completely pleasant, fair, and quick process. I have never tried to trade in a Mac at an Apple store. If Apple lets you do that, I recommend it.