Great to get the hi-res clarity on the Bluray of course - but a comparison with the DVD (also in this package) reveals another advantage: the DVD aspect is cropped top and bottom, probably to widen the ratio out to standard 4:3.
In fact the original aspect ratio is 1.19:1, quite close to square. This was common to early sound films, I understand, when room had to be made for the soundtrack, on the side (as projected). Best comparison is with the early images of the scorpions: the iris around the images is a complete circle on the bluray but cropped on the DVD version.
The booklet too, is slightly smaller than the earlier BFI DVD-only edition - format aside, there are fewer illustrations and the facsimile of the original L'Age D'Or program is missing. A bibliography for the key essay is also missing.
The movie material is sterling, of course, though bonus material appears only on the DVD. Robert Short's introduction is informative and worth a listen, though you should mind the commentary for L'Age D'Or: it actually abbreviates the movie - so leave it off until you've watched it at least once.
The documentary A Proposito de Bunuel also well worth while - one of the few places you'll find photo evidence of Marilyn Monroe's visit to the set of Exterminating Angel (with Jacqueline Andere's anecdote on the occasion).