If you are planning for invest then ok but if you want to use the flat for your own use then I do not think it is a good idea. Hennur is not well developed yet and there is a great need of infrastructural developments.
The area has witnesses price appreciation and it is expected to up in the next one year. Investing in Hennur is a good idea. If you want to sell your property after few years you can expect god returns.
Recently, South India based, Mantri developers Pvt Ltd has launched Mantri Web City, India's first techno residential project located on the fast developing Hennur Main Road.
The area is also surrounded by many educational institutions, hospitals and IT Parks. the area is also close to Bangalore International Airport. So I feel it is worth investing in this area.
It is predicted that in the coming years, the locality is likely to see a new dimension because of the close proximity to the airport and planned developments. So You can expect good appreciation as well as return.