We have been to many of the Loire chateaux. Beauregard is amongst the most expensive at E12.50, and offers about the least in our experience.
The chateau itself is not of great beauty as far as the exterior goes. Internally the high spot is the long hall with 327 portraits of characters of c the late 16th Century including Henry VIII and Anne Boleyn. The hall is rather murky though as the windows are heavily covered presumably to protect the paintings. Apart from that internally there are only 5 other rooms to see which contain nothing of great note.
The park, which is much heralded in the publicity material is pleasant but nothing exceptional, except for the garden of colours. This should be spectacular as it is twelve different areas each containing a different coloured selection of plants. However, due to neglect some more vigorous plants had taken over, some had disappeared and the colour scheme had become somewhat mixed. This should have been rather special but had deteriorated.
Finally I think it is a bit of a cheek to charge this much - to compare, Blois charges E9 and Chenonceaux E11, and these are both vastly superior experiences. Then they do not even bother to provide toilets! Unless you really must see the gallery best to avoid.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.