Well it depents on what you already got and from which year it comes the remaster, and if you're interested in Elvis music as a whole, or just about certain moments in his career.
I think the box its a winner and does justice to Elvis recording carreer as it never ever before. Now we have to understand that elvis recording career as a whole is five times the amount of material recorded by the beatles, so yes, the box is huge and turns out to be way expencive, and of course not all of what Elvis recorded is great, but being a "Complete" set, bad stuff like some of the soundtracks had to be there. But its all put together in the right context, the book and the box art is perfect to me for that purpouse.
Maybe a "Selected Works" version of it, containing 15 out of 30 CD's, reducing costs, with just the good stuff, could be the "Definitive Set" at one point in the future, but the "COmplete Masters" set it was something that historically had to be done to preserve and reevaluate Elvis musical/recorded legacy (the whole bunch I mean).
I gues it is just not a product for every fan, not even aimed for the die hard fans, but it was mostly thinked as a tribute-statement about Elvis remarkable recording carreer, kind of an academic enciclopedic job where EVERYTHING IS FINALLY PUT IN ITS RIGHT PLACE AND IN THE RIGHT WAY/SOUND, as Elvis catalogue for many decades was a total mess.
I wouldnīt recomend the get the set for Elvis starters. If I'm asked how to start an Elvis musical collection right now, I would rather point at: Elvis '75, then if there is more interest: each and everyone of the double CD/double album Legacy releases to date and to come, and the Legacy Box set: Young Man With the Big Beat.