I like these sets. If you consider them "core samples" of person's (pre-WWII) career you'd be close to the feel of them. The Bunny Berigan and Joe Sullivan sets actually got me into those figures; the others were just nice additions to what I already had. The Ellington box has got to be my all-around favorite Ellington anthology, even more than the Smithsonian, just on sheer listenability. Not all the booklets are equally good, but the average is quite high, and some of them are just a joy due to the combination of info and good writing.
Frankly, I think there is still a great need for anthologies like this. Well-done, reasonable-length overviews done for the general public rather than overwhelming super-complete megaboxes for the specialist (though I have my share of the latter.) I really, really, (really!) hate to say it, but the closest thing on the market now are probably those Ken Burns compilations, but they are limited to only one CD per artist, which seems a tad slim in some cases, though good for newcomers. And why did Burns & co. feel compelled to make the covers ugly as sin? Ah, well...
In short: Hell yeah, if you're into vinyl and see some of these Time/Life Giants of Jazz boxes in good condition at a cheap price, believe me, you could do a lot, lot worse. They be good.