We visited the Central Synagogue on the same day we went to St Stephen's. It cost 200 HUF or about 60p to get into St Stephen's with all its beauty but it was 2500 HUF or about £7.50 each to get into the Synagogue (500 HUF to take in a camera). It was nothing very exciting and was not particularly interesting inside. The only plus was the different staff who gave short talks about the Synagogue so you got more information about the history. There is a small garden and museum at the back of the grounds but they are not that interesting. It is not value for money and I would avoid this unless you have a special reason to visit.
If you own or manage Great / Central Synagogue (Nagy Zsinagoga), register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.