It’s a wonderful work of scholarship and an absolute necessity if you are doing any kind of Latin academic work. It’s a bit overkill for the average Latin self-learner, though. It is amazing to read up on a particular word when you have the time, but it’s not too handy as a quick reference for when you are just working your way through a text and need a definition. Depending upon where you are in your studies, you might want to hold out a bit and see if a sale pops up. During Oxford University’s Fall Sale in 2007 the price was $135 (vs. over $300 regular). That’s when I picked it up:
http://discourse.textkit.com/t/some-deals-that-might-be-of-interest/6977/1
Of course you never know if or when a sale like that will come around again. Being a rather new book (at least, on the classical time scale), it is still under copyright and there are no digital versions (unlike some of the other great works: Lewis & Short; LSJ) so if you want it, you’ve got to get the real thing (though there is a digital version in the works: http://www.logos.com/OLD we heard about it awhile ago, but nothing lately, so no idea where it stands).