There's a reason people go to (certain) BMW dealers for service. I've been there; I get it. You're treated like royalty. You're addressed as Mr. or Ms., not by your first name (like you're a long-lost drinkin pal). The waiting area is spotless and pleasant, with wifi and several HD TVs. They wash your car after every service and put paper on the floor. And then you pay for it -- Ouch! And if they can't fix your car's problem the first time, or the second time, or the third time, that's ok because they're such pleasant, customer-first folks! Just pay yet another inflated bill for the same non-repair and enjoy it!
ABS is different. There's no cheery SA greeting you with a mobile device into which they enter your Customer Data. ABS knows BMWs and fixes them right (in my experience) and at reasonable cost. How many BMW-know-it-all-but-fix-it-cheap customers have they dealt with over the years? The staff is not pleasant but they're not unpleasant. Sometimes they're very cheerful and sometimes they're gruff. I make no apologies for them. I can imagine some customers (especially some BMW owners) getting indignant at not being pampered -- and of course, it wouldn't hurt business for ABS to be always pleasant all the time -- but to each his own when deciding on what's important in a competent repair shop.
I want my car fixed by someone who knows what they're doing and I'll pay to fix it right the first time. The dealers cannot be depended upon for that, only for providing a sumptuous visiting experience, at a VERY high price. ABS knows why you're there and not at the dealer. You're tired of being ripped off by smiley but incompetent and overpriced dealership shops. Just go with the flow at ABS and be happy that your car is fixed right.