Now while the remasters have new liner notes by Max Bell, the box set has a substantial booklet.
There are pros and cons about which to go for. For someone who just wants one collection of E&TB, and although there are several best of's, I'd recommended this lavish box set. But it doesn't tell the full story. Ian McCulloch used to rant on about Ocean Rain being the best rock album ever. He's wrong, of course, but not that far wrong and it should be in every rock fan's collection. Buy the box set and you miss a number of great songs and the same can be said of the first three albums.
I recommend you do what I did. Get the box set (which, at its current price, is a bargain - it's aroudnn £16.00 and despite having a digital copy, I'm still thinking of buying it), revel in it for a while, and then go back and buy the remastered extended versions of the first four albums, plus maybe a later live set for a bit of variety. (I picked up Live in Liverpool, 2002, which is nice but nowhere near the live disc on the box set.) But whatever you do, even if it's just buying Ocean Rain, you win.