It’s essential to look at your wider installation before making this decision. Remember that the Pixel Strip and the Power Supply must be the same Voltage, and the Pixel Driver must support that Voltage range.
5V Pixel Strip is more susceptible to Voltage Drop’s effect than 12V Pixel Strip. This means that you can run more 12V Pixel Strip without the risk of a dip in performance furthest aware from the Power Supply.
Previously 12V Pixel Strip was grouped by 3 Pixels; however, since the release of ENTTEC’s 8PX60-12-B 12V RGB individually controlled Pixel Strip the demand for 12V strips has increased considerably.
If you want RGB Pixel Strip, then the 8PX60-12-B is a fantastic solution. If you require something other than RGB, then a 5V strip is the only solution since the 12V individually controlled Pixel Strip technology hasn’t expanded into RGBW (or different configuration) Pixel Strip.
If you are after a bright strip, the grouped 12V Pixel Strip provides the most lumens per meter. The 5V Pixel Strip remains the brightest individually controlled LED Pixels.