Never used BMW Roadside Assist, but my wife had a flat tire and called them (she would have changed it, but it was pouring rain). Just under 20 minutes to arrive, and then he followed her to a nearby tireshop to drop the flat tire off so that he didn't have to put it in the trunk wet. She was impressed. Small sample size, but the contractors they use here seem to be pretty good.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue