I don't think so. The purchasing experience is very personal and therefore very subjective.
Two people describing their PDI can tell you completely different things, for example
Couple # 1 "The salesman was very nice.He was very thorough and covered every aspect."
Couple #2 The salesman treated us like a couple of idiots,I mean who doesn't know how to light a stove, this jerk droned on and on for two hours!"
I guess research like you would any other merchant you a spending big bucks with. Check longevity, BBB customer service review sites.