The only acquisition I can think of a decently operated company purchased by a much larger company that resulted in a positive outcome was Garmin's acquisition of the Delorme GPS satellite transceiver company. I've had units from both Delorme and Garmin, and the product line (and customer support) has been much improved by Garmin. It's notable that Garmin isn't PE (it's publicly traded) and the Delorme technology was something closely related to Garmin core business technology focus. I was relieved that Garmin didn't buy a competitor to kill it but rather to gain access to some very useful satellite communication patents and access to a satellite communication system. I don't believe Garmin had any communication capability prior to the acquisition.
So many acquisitions follow the PE model mentioned previously in this thread; acquire, skeletonize, and spend down customer goodwill that took years to establish. PE partners are seldom motivated by any sort of personal affinity for the company's products...they're solely interested in a very high rate of return by any means and then moving on to the next available 'opportunity'....frequently a successful company whose founder(s) want to 'cash out' of the business for any variety of reasons.
Hobie is a good example. While Hobie products have always been pricey they were also innovative and supported by steady improvement and decent dealer/customer support. That all ended when the firm was purchased by two successive PE ownerships, which proceeded to run the operation into the ground by abusing dealerships and customers.
Hobie has now been purchased by Bass Pro and all of its manufacturing equipment has been moved out of Mexico (where it was relocated from Southern CA by the PE owners) and into Bass Pro's White River boat manufacturing facility in Missouri. While I'm not optimistic that Bass Pro will ever resurrect Hobie's former innovative approach I'm somewhat hopeful that they'll support neglected customers and the Hobie dealerships. I've talked to several Hobie dealerships who are actually relieved regarding the acquisition because they're starting to receive some Bass Pro Hobie kayaks and parts inventory after years of abuse by the PE owners, and I've looked at a few Hobie kayaks being sold at Cabela's and can't really see any difference in quality.
I don't see Bass Pro continuing to offer the really high-end 360 drive kayaks that have proven to be very problematic due to their mechanical complexity, but Bass Pro says it will honor Hobie's warranties for those boats. I think they'll stick to marketing Hobie's far more established and reliable lower-end models. Maybe I'm wrong because bass fishing from kayaks has become a big deal in many parts of the US, with kayak bass fishin' folk spending huge sums on all sorts of exotic kayaks.
At least Bass Pro isn't a PE outfit and it's privately held by a longtime owner that's alleged to be a fishing fanatic. I've heard Cabela's went to hell (especially regarding warranties) when they were purchased by Bass Pro, but I don't personally know that's true because I never frequented Cabela's all that much. I do know that a great many firms have stepped back from warranties in general...largely because of customer abuse.
Time will tell......greed alters most things.