As far as I can tell, the bad voltage regulator (which shows itself as a noisy baro that can't hold altitude well) comes from all of the Chinese venders. Sometimes you get a good one, sometimes a bad one. Fortunately, the fix is to simply remove (unsolder or cut trace?) a very tiny component.
Usually, the Revo's will say Revo, or Revolution, so look for Revo(lution). It will also mention an MS-5611 baro(meter) and a STM32F4(05RGT6) processor
banggood and goodluckbuy are good places to look for Revo mini. The expensive one has telemetry built in. The less expensive one requires buying a telemetry add on, and may even be cheaper if you include that price.