Den Boomband is really a good internet provider.i have been using this from last 1 year in Delhi and I have no issues regarding their service.if I face any problem then they solved the problem within 24 hours.bt from the last 8 month or so I did not face any problem regarding speed or connectivity.
Also major usp of Den is that they provide a constant speed and their is no fluctuation in the speed like other networks in the area.connection reliability is excellent for me.
Also their service and support department is very good and fast and their employee or boys are very cooperative while they come for the service or to solve any issue.
So think in Delhi this is one of the best internet provider.