I uses the completely free software program called Diogenes:http://www.dur.ac.uk/p.j.heslin/Software/Diogenes/
It includes not only the LSJ but also the morphological analysis tool from Perseus. The only potential advantage of the paid version you are looking at, from what I can tell, is that it includes the 1996 supplements to the LSJ, while the absolutely and completely free version has the 1940 edition. Also, Diogenes only allows unicode input, but that's what I prefer anyway.
Let me just tell you how incredibly cool and useful Diogenes is to me. I have it autoload when my computer boots but I keep it minimized in my system tray. With a little bit of setup, I have my firefox browser set to use that diogenes as my default search engine. Any greek (or, by the way, latin) word that I encounter I can simply highlight with my mouse, right click, choose "search Diogenes" and firefox will open a separate tab with a full analysis of the inflected form and dictionary entries from both LSJ and the Middle Liddell (or Lewis and Short for Latin words). It also has its own interface, so if you are using any other program you can still just copy and paste the word into the main screen of the program and get the results that way.
Did I mention that it's completely free?