Gaining insights from a relative handful of anonymous product reviews requires patience and skill at reading between the lines. Anonymous reviews of replacement auto parts are even sketchier. There are just too many parts and too many vehicle models to ever hope to get a meaningful number of useful reviews for any one part. RockAuto may have ten alternators with a choice of three amperage outputs that fit just one truck. Reviews of broad part types (alternators, thermostats...) and brands (ACDelco, Stant...) without any specific make, year, model, engine connections are likely to be nothing but vague opinions and biases. RockAuto's heart icons () turn the extreme specificity of replacement auto parts into an advantage! A heart icon next to a part means it was ordered most frequently and returned least frequently for a specific vehicle. This is actual data from ALL customers facing similar repairs on the same vehicle. That is what makes heart icons great. They are based on data that automatically reflects the myriad things ALL customers purchasing that part for that vehicle have taken into account.