It is free.
It has a key-stroke shortcut, Ctrl -Alt-S, to activate text to speech. Using the space bar starts and stops the reading of any text you highlight and starts and stops continuous reading.
The voice it used seemed pretty natural and you can speed it up or slow it down by accessing the settings in the Library home page under settings and the accessibility tab.
You can highlight text in various colors and add sticky notes.
Highlight a word and add a tag, note or website link.
Books you purchase can be set up into folder categories, i.e. history, literature, science, etc.
You can set up media stacks for newstand purchases in chronological order.
There are many college and professional trade textbooks in e format.
The Nook Study syncs with other Nook apps; i.e. books I purchased on a Nook App on an iPad show up on the computer on Nook Study.
There are many free classics and public domain books available. (Check out Calibre for formatting pdf's and other documents and managing/adding to your e reader libraries)
Textbooks available in a Nook format are limited. You are not going to find a fourth grade social studies textbook.
Not yet available for portable devices.
I would check out this free download if you are looking for a text to speech accommodation and want some study helps. I am loving it.