4Yanx:
Yes, I am quite confident that Erroll Garner falls into the "underappreciated" category. Ask the vast majority of people about Erroll, and they'll give you a blank look. Even if you ask people who have some interest in jazz, you will find that most of them know little about Garner, and probably have not heard anything but "Concert By The Sea".
I had the good fortune to hear Erroll Garner several times during the 1950's, both in concert and in clubs, and his exuberant, joyful music remains with me even today.
Should you and I start an Erroll Garner fan club?