I have a new car with up to 2 free oil changes within the first year, once the OLM displays "change oil". I will be doing it myself regardless (even under warranty) and keeping both written records in a book and receipts of all parts/fluids/filter purchases for warranty purposes according to the Warranty Information booklet.
Personally while working at a quick lube, I have worked with some "technicians" who are very thorough, always change the filter, replace drain plug & gasket if needed, make sure correct oil is filled, customer is happy and don't push upsells super hard, etc. but you also have those who do not care or are simply not trained well. At this place, I saw a truck where they drained the transmission and double filled the oil. Was an automatic trans (based on hydraulics) so it didn't shift out of first gear so the guy brought it back, realized their mistake and fixed it. The tech checking the oil clearly didn't care since it would've been way way up the dipstick, and it should've been caught before they left. I still wouldn't be happy even if i essentially got new trans fluid for "free".
While working at a dealer, as stated above, there are thorough technicians where every thing is tried to be done perfect, where the fingerprints are wiped off the dusty engine cover, dash display is set back to where customer had it, etc. I have also seen experienced dealer technicians of 10+ years leave an oil cap off w/o oil in the sump, drive it a good quarter mile, engine kills itself because of absolutely zero oil pressure (i assume), they realize their mistake and fill it quickly with bulk oil from a jug supposed to be used for coolant and sent it on it's way. The customer never was told, and you wouldn't either if this happened to yours. That engine surprisingly didn't knock afterwards,but I do wonder if it has consumption problems now.
I do recommend dealers over quick lubes because usually the oil change techs have/are in some sort of Automotive Technician program, and/or do oil changes often on the same vehicles so they know how to do them well and properly. But mistakes will always happen, regardless.
The unfortunate answer is if you want it done right, you should do it yourself.