Having seen this and had time to collate my thoughts here are a few of them.
Firstly the design is very different from the original. The designers have used a combination of Hugo's own paintings and some new (Dore influenced) plates. These are projected using a highly sophisticated system and look very fine. However the combination of what is essentially projected "cloths" and solid scenery actually conveys a rather traditional and conventional stage picture. It is certainly less interesting and fluid than Naper's groundbreaking original designs. However the simplifying of the set and the loss of the revolve and large barricade trucks make a production which can be loaded in and out in a much shorter timeframe than the old touring set. Money talks....
I found the direction of the new team adequate but no more. They have clearly absorbed some of the complexities of Hugo's vast work but this has led them to add some spoken lines which are inserted (rather hurriedly) into gaps in the through sung score. The lines are meant to illuminate aspects not covered by the existing score but for me they emphatically do not work as they feel forced in the context of a through sung piece. A pity that some proper re-composition couldn't have been effected.
So much of the direction just fails to add anything new to Nunn and Caird's extraordinary original. A typical example is the suicide of Javert which is quite a complex sequence in this version. It is reasonably effective but compared to the brilliant simplicity of the original solution it fails to come up trumps.
The sound was for the main part good with a full, fat sound picture. My only quibble was occasional odd sounds from relay speakers which almost felt like an effect without the original source - Odd.
I was slightly disappointed with Paule Constable's lighting. She is a designer I usually admire enormously but here she seemed so intent on not aping David Hersey's iconic original look that she failed to put her own stamp on it. Incidentally (IMHO) the use of roving lights to signify the shots at the barricade does not work at all - They just look like searchlights which is incongruous in a work set in 1832.
The cast are mainly good without being exceptional. John Owen Jones is an effective and well sung Valjean (an ugly breath before the final note of "Bring him home" excepted) but for me he just misses the titanic emotions that Colm Wilkinson brought to the part. Best of the bunch is Earl Carpenter's Javert who is almost on the same level as Philip Quast (I can't think of higher praise in this part). The Thenardiers go some way to reversing the misconception of the roles as merely comedy parts. Anyone who has read Hugo will understand how wrong this view is. Unfortunately they are still saddled with the school of panto costumes for the Wedding scene - I sense the hand of Mackintosh here!
So to sum up - This is a worthy attempt at a re-think of the original which will allow the producers to take it into theatres previously unable to host the show. But it is unlikely to replace the groundbreaking original in the longterm.