Opentype features functioned under MAC OSX < 10.8. Mountain Lion with iWork (Pages, Numbers, Keynote).
Unter Mountain Lion with Pages 4.2., Numbers 2.2., and Keynote 5.2. there are serious bugs in accessing the opentype features which are usually activated via the typography panel (cmd+T). For instance in all three programm its utter impossible to activate true small caps via the typo panel. Also all three programmes have serious kerning issues. All these problems didn't exist before Mountain Lion and under Pages 4.1., Numbers 2.1., and Keynote 5.1.
I have reported these problems to Apple's bug reporter but no reply so far.
Its also impossible to run Pages 4.1. under Mountain Lion to get around this problem.
Its interesting to note that TextEdit (1.8) under Mountain Lion does not have any problem to activate the opentype small caps feature or to do the kerning.
The screenshot shows Fakt font from Ourtype in Pages 4.2. (no small caps possible via typo panel) and TextEdit 1.8. where it functions. The same problem is true also for other opentype fonts like FF Ernestine Pro or Adobe's Minion Pro. All of this worked excellent under MAC OSX Leopard and Lion.