The advantage of a dealership service center versus an after market shop.

 
Pictures of an N63 engine with bank 2 cylinder head removed. Not an easy job. A dealer will get this done right.

Same engine from the front. Very complex wiring and hose layout that needs to be exactly where it was before it came apart. Hydraulic table being used to drop engine from underneath.

       I've seen this so many times. I go online out of curiosity and search for forums and find many people that refer to the dealership as the "stealership" referring to how expensive they are. Believe me, I know that repairs and maintenance on luxury vehicles can get very expensive, but like anything else, you are paying for what you are getting. Let's compare for example a simple oil change. A dealer might charge you $100 for an oil change on your BMW. For this price you have a certified, experienced automotive technician using factory original parts performing the service with the correct factory recommended engine oil, resetting you CBS (service interval) data correctly and performing an inspection on your vehicle. The technician working on your car knows all the details to be able to perform the service correctly and efficiently. He knows how to top off the fluids and has the correct fluids that your car needs. He also knows what key areas to inspect on your particular model to see if parts have failed, like engine gaskets, suspension components, etc. You would then get an estimate for repairs to be performed by this experienced technician with original parts and get a warranty on the parts and the labor. The repairs would be done efficiently and correctly. You would be waiting in a nice facility with TV, internet, and sometimes free food. By contrast, I have heard of people who have taken their BMW to an aftermarket shop or quick lube place, paid MORE than what the dealer charges to perform an oil change, seen time and time again how their engine oil filters don't flow oil properly and have seen some just come apart when you change them out because they don't hold up, and can cause issues with the engine. I have seen time and time again how these places strip the drain plug and damage a $1000 oil pan because they probably used a damn impact gun to put the plug back in. And after all of that not check tire pressures or fluids on the car and not even reset the service indicator because they just don't know how to.
         That was just an example of an oil change. I have seen so many repairs performed by aftermarket shops. I would say about 10-15% of them might know what they are doing, but most of them don't. Of course to the untrained eye of the customer everything might be fine and the car runs again, but we can spot the shitty workmanship right away. Hoses and wires routed the wrong way that will eventually cause issues due to rubbing, parts not installed correctly, parts getting broken trying to replace other parts, parts completely missing. Parts can break while you are working on a car. It's normal. You might be trying to change a thermostat and the coolant hose that attaches to it can just crack. This is normal wear and tear of the parts due to heating and cool down cycles or just because of the age of the vehicle. The difference is that if that same hose breaks at the dealership you would get a factory replacement hose, not some aftermarket shop trying to use a hose clamp, duct tape and bubble gum to try to put it back together. We know where everything goes and how to route wires correctly, and if we don't remember we can just go around the shop and look at another one of the same exact cars and see how everything goes back together or we can ask someone else that might know.  The point is that your car would go back together correctly and safely. We can foresee potential problems with repairs and warn the customer before it happens. We know improper repairs could leave a customer stranded and that is unacceptable. We get the job done right (most of the time at least).
        And now for the big one, DIAGNOSTICS. You might be days looking online and searching on forums for what's wrong with you car. It might be something simple or complicated. It may happen a lot or intermittently. No matter what the situation is, I believe the best people to diagnose you car is the dealership. We have all the information we need to properly diagnose a vehicle. We have the proper tools to test and perform repairs. We have the correct parts and we have the correct software. I will do another post detailing the diagnostic process in more detail, but please believe me when I say NOBODY can diagnose your BMW like BMW dealer technician.
         Another big thing to consider is time. A dealer will try to get you car done as soon as possible, usually within a few days depending on the complexity of the repairs, while independents will usually take longer. Just ordering and getting the parts they need might take them a few days. So if time is essential, like for example if that is the only car you have to drive and cannot afford being without it for a week and a half waiting for a dumb ass to figure out what's wrong with your car and then try to fix it, you might want to take it to the dealership.  I know some people may have had bad experiences at the dealership, and maybe their issue was particularly hard to figure out, but I bet if you took that same car to an independent it would have been way worse. I know of many cars that have come to us from so called independent shops specializing in European cars because they couldn't fix it and we have figured it out in a matter of hours.
        I know repairs are expensive, and a lot of times the parts alone are ridiculously overpriced, but if you can afford the dealer prices they are definitely worth it. Why have someone else waste you time and money experimenting with your car when you can get it fixed quickly and correctly and be back on the road in your ultimate driving machine.

               N62 engine after being removed from vehicle. It still has wiring harnesses, hoses, etc.

                                  N62 engine stripped down to block, pistons and crank. Only a
                                               professional should attempt this type of work.