I have been living in Delhi from 2010 after I moved to Delhi from Kolkata. I found that the Delhi Metro is far better than Kolkata Metro. Its very neat and clean and the frequency is very high.
There is a special coach for the ladies as well. The timing is from 5:15 to 11:45 so the late night commuters can also take advantage of the same.
Moreover it had made Delhi, Gurgaon & Noida closer to each other.