Where to service?

[Capra]

Hey guys,
My 65 C Class is due for service. Mercedes dealers are so expensive. I was thinking of servicing it at Halfords or KwikFit or a local garage. Which one would you prefer? What are the differences?
Thanks

Before my first service last year I went to quick fit as the online quote wouldn't work, they told me that they couldn't service it. Not sure if that means, "you wouldn't want us to" or "it's too complex a job for us"? In the end I was happy I went to a specialist.