Been a couple of times. One of the times we went the Webb Ellis trophy was on display, whilst it was doing the tour before the world cup in Japan.
Has some nice displays of memorabilia etc and some interesting facts etc on the walls, went just after it opened the 1st time and had to point out Bill McLaren was Scottish. Worth a visit, or would be if it was ever to open again.
Find it hard to understand why they have to pay a license to World Rugby to host their museum.