I have heard these but have not listened to the older HLP3ES2. I have listened to many bookshelves. PMC, Dynaudio C1, 1.3MkII, Proacs, B&Ws, Sonus Fabers, Marten Dukes, Totem Model 1. While each have their own sound signature and special in their own ways, I find the P3ESR to somehow possess a very musical, organic and easy-going sound without losing any details. They seem to communicate the essence of music more effectively compared to the rest, to my ears. I can definitely listen to these for endless of hours unlike some speakers mentioned above due to their extremely low listening fatigue. A friend of mine who owns the 40.1 was so smitten with the P3ESR that he got himself a pair while few other pairs of monitors keep stacking in his storeroom.
As for P3ES2 vs P3ESR, the thread below might be of interest to you.
http://www.harbeth.co.uk/usergroup/showthread.php?t=620
As for P3ES2 vs P3ESR, the thread below might be of interest to you.
http://www.harbeth.co.uk/usergroup/showthread.php?t=620