I love going to the dealer for service. If you want your car to operate the way it was intended and as long as intended, you should go to the dealership.
What I don't love about the dealership is paying dealer prices and service charges. So if my car isn't new and isn't under warranty, funk that! I'm taking it to a local mechanic!
Now choosing the right mechanic is a task in itself. A mechanic isn't just a serviceman. A mechanic is an ally you build relationships with. A good local mechanic will treat you right. Most items will come with suggested service and every mechanic will "suggest" certain repairs. Many people will complain and assume they're trying to get ripped off when in fact, some just don't understand the maintenance required for an older car. Belts, hoses and stuff wear over time. So while you've gotten a motor opened up, why not replace the gaskets?
I am not a mechanic, but I know enough about cars to make some my own repairs. My problem is laziness, but that's a separate discussion. MP Motorwerks is a shop I trust and they've never steered me wrong.
I've had repairs done on an old 5 series with 279k miles here. I've also had some repairs performed on my 85k mileage Mini. While the prices aren't as cheap as repairing a Honda, it was definitely more affordable than the BMW dealer.