The refurbishment is poor, and the new curation pretty awful too - a superb museum has been seriously undone.
The museum formerly had light galleries either side, lit from the ceiling mainly by daylight, and large terraces in front of the main stairs at the end of the hall, which had space for exhibits and for visitors to look out at aeroplanes from both wars and a V2, and down onto the main floor where there were tanks from both wars and a WW1 era bus for driving soldiers to the front.
Now the roof is obscured and everything is artificially lit. The main floor has been lowered to basement level by excavating, and two new steel staircases have been added, one at the terraces end in front of the terraces, and the other at the main door end. These stairs do not easily allow visitors to look out over the hall, whilst at the terrace end they obscure the view from the terraces too. The P51 and all WW1 planes are gone. A huge Harrier jump jet occupies most space, and is too big to view. You can no longer view from the earlier small terrace at the front end - it has been removed. The WW1 tank and bus are gone (why, especially in the centenary of WW1's outbreak?!?) and the main hall accommodates many fewer exhibits.
The sides of the halls have inexplicably had clunky great columns added, from which peer the snout of a desert landrover and the front of a Dunkirk jolly boat (why? We can't see them well, and they're made to look ridiculous.)
Many of the exhibits are big glass cases rearranged in GCSE History manner. For example a map of the North Sea, a tiny model of a surface vessel, and a piece of tailplane from a shot down Heinkel. Why? Can't we think for ourselves?
The lighting is harsh, shadowed and disagreeable compared with its earlier, pleasant arrangement.
This museum is still worth visiting but there is no getting away from it - the museum has been badly damaged at vast public expense (I read £40m,) and is a shadow of its former self. Fosters Architects should be absolutely ashamed - their work fails practically (the absurd, unneeded stairs, cluttering and obscuring, and the removal of daylight,) and stylistically (Fosters should have thought hard about the skill of their predecessors and the need to make any stylistic change whatsoever.)