Been twice last year.
First time I was on a service call in Birmingham and called in as i hadn't been for years and wanted to see what they had done with my two bricks !
[ During the initial building of this museum they ran out of money and made a public appeal, buy a brick for £10, so as I thought it was a good cause I bought two bricks, didn't see mine as they all look the same

]
Loads to see but it doesn't appear to be laid out in any order by make or year. I wandered round and it was interesting but by the time I got to hall 3 of 5 my brain had gone into overload, Oh look there's a Triumph, Oh look there's another Triumph etc and i skimmed the rest and left rather disappointed but not really knowing why. later I worked out it was because I was on my own and it's too much to take in.
Couple of months later I had to attend a small exhibition there in one of the show suites and went with a colleague who is also into bikes. The show ticket also gave a free museum ticket so we did the show in 20 minutes and went into the museum for 2 hours

Far better this time, partly as I knew what to expect but mainly as we were pointing out features to one another, only regret is I left my camera behind.
There are some very rare beasts there and it's easy to image what the industry would have been like if the various designers had not been strangled by management.
Take a look at this as an example from 1952
http://motorbike-search-engine.co.uk/classic_bikes/1952-bsa-mc1.phpProduced at a time when the best we had were plunger frames and staid engineering.
John S.