I am using docomo network since 4 to 5 years. Docomo has improved a lot from past few years. What I like most in docomo is the price at which they provides the internet services.
The speed of the 3g is very good but there are some areas where the networks dosent work, while other networks work properly. Sometimes, I am not able to receive the constant net connectivity. If this problem is solved, then there is no need to switch to other operators.