In writing papers, sermons, even letters, I've found this resource to be invaluable as a "quick check" to be sure I'm using a word correctly, look for a better word, or check my spelling. As for features offered, the program gets five stars in my book. The problem is that Merriam-Webster has apparently taken their Windows version of the program, with all of the clunky, non-intuitive interfacing that goes with that platform, and simply "tweaked" the code to make it work on a Mac. A few examples: 1. Once you've searched for a word, you have to double-click in the entry box and delete the first word before you can begin typing a new search word--whereas Mac standards dictate that you'd simply Tab back to the field to select all and start again. 2. There's no hot key to toggle between the Dictionary and Thesaurus searches, or between the Basic Search, Advanced Search, and Browse functions--you have to choose these features with pop-up menus and tab buttons. 3. When you launch the application, it opens a window that is pre-configured for a 17" monitor. No problem on my desktop G3--but on my iBook the window is partially off the screen, so I have to shift the window manually to see all of it. Furthermore, though the window frame resizes, the CONTENTS of the window do NOT resize--and there are no scroll bars to see information that may be hidden if you shrink the window too far. (NOTE: the window does fit--just barely--on an iBook's 12.1" screen.) Small problems, to be sure, but for a resource that's primarily used "on the fly" while working on other projects, anything that slows me down is frustrating. Still, I do use M-W daily, so I do consider its purchase price money well spent.