With space for 15,000 worshippers, Masjid Negara is certainly very large.
It completely dwarfs Masjid Jamek, which it replaced as KL's most important mosque when it opened in 1965.
As far as attractiveness goes, it's a bit of a mixed bag. The white walls, and outside water features, are not unpleasing to the eye. But whatever aesthetic virtue the building may have we think is ruined by the shape and colour of the roof.
It is possible to walk safely from Pasar Seni to Masjid Negara now via Kuala Lumpur Railway Station.