I first auditioned the FB1+ and I really like it's sonic qualities. Sonically the FB1+ is much better than my Sonus Faber Grand Piano. Then I listened to the OB1 and that pretty much sold me.
The OB1 sounded even better as soon as I got it setup in my medium sized living room.
I am sure as you go up the PMC line, the better its sonics. Good setup and synergy helps.
Thanks!