Hi Hawkbyte,
Thanks for your interest! I have to be honest, we have no such guidelines i'm afraid! It's a very good point though and i've added this to my list of "fine tuning" for next year. For example, as you say, in my mind 3 stars is good, 2 would perhaps be "good in 1-2 areas but overall not for me" and 1 would be "unfortunately nothing here appealed or worked for me."
Thanks
Adam