The brake booster vacuum pump switch affected automatic 1.4T Cruzes. Small turbo engines generate no vacuum of their own at a high idle and in gear, so the assist pump is there to provide vacuum to the brake booster. It was a faulty part, and the cars were recalled for it. If replaced with a good part (98% of them were), there should be no more issues with it.
I would stay away from Cruzes that are:
1. A 2011 model year.
2. An automatic. Just too many issues/leaks with the auto transmissions in these cars - transmissions are something that GM has never been great at.
3. Have high miles for the model year or a sketchy service history (the LS you were looking at). Heard the phrase "driven hard and put away wet?"
I would, on the other hand, recommend a manual 1.8 or 1.4 Cruze with a clean history and manual transmission.
If you're looking for a good family car, I think a Mazda 6/Fusion, Ford Escape/Mazda Tribute, 03-07 Honda Accord/CRV, or 2005-6 or 2009+ Toyota RAV4/Camry would serve you well (avoid 07-08). The 2008-2012 Malibus weren't terrible cars either. Maybe it's just me, but I'd want something bigger than a small car if I had a family.
My experience with buying a 140,000 mile car was that it is right at the point in its life where many things begin to need to be replaced (suspension components and rubber things especially). That car (a Volvo) has a ridiculous reputation for durability and it is still on the road today at 243,000 miles, but it has definitely needed work (not powertrain), sometimes quite expensively, along the way.
If you read enough reviews about ANY product/car/etc. on the Internet, it'll make it look like a piece of crap - yep, even a Civic/Corolla. These are machines built by people, and people inherently screw things up sometimes.