Taurus Firearms themselves aren't usually bad. In fact, more often than not they make good lower cost firearms. The real problem is their Customer Service which is quite possibly the worst among mainstream firearms manufacturers. Taurus firearms only appear to be of deceptively poor quality because folks who got a lemon often have to play telephone tag with CS, pay for shipment both ways, wait several weeks, and more often than not get the firearm back with every part replaced save for the faulty one, which in turn results in them telling the story out of pure bewilderment/disbelief. As a result, the take away by most folks from the outside looking in is; "All Taurus firearms are lemons." due to the sheer number of reports of terrible experiences with CS.
In reality, I would estimate that the actual number of lemons turned out by Taurus are no more than Ruger, but the difference is that Ruger tends to have good Customer Service, ergo reports of problematic Rugers tend to be much smoother and reach a satisfactory conclusion which the average consumer only even bothers to recount in the event in which they are active members of firearms forums where threads regarding the quality of Ruger CS are posted.
Between my family and I, I've had personal experience with a total of 5 Taurus brand firearms, all of which have been thoroughly tested, and have proven to be mechanically sound.