BJP and Congress are fundamentally different from each other.
Ideologically, BJP is a nationalist party. It was the only political party during Atal Bihari Vajpayee’s regime that delivered whatever it promised. Congress is more of a political party which believes more in divide and rule.
BJP believes in Hinduism as different from nationalism, and they as much believe in other religions, Congress talks about Hindus and a separate Hindu nationality.
BJP is more a democratic “political party”. Congress is the fiefdom of the Nehru family where anyone willing to kow- tow can get an entry to serve him or herself.
BJP has a very strong cadre base, you can make yourselves heard if you are an active karyakarta of BJP. In Congress, you have to be convincing the Gandhi family to bring about any change.
Sri Narendra Modi can head the BJP, but its not possible in Congress where only the ‘scion’ of the Family can take the highest position. Rahul Gandhi who can be worth nothing will head Congress and can become PM if Congress comes to power.
BJP leaders are in a better frame of mind for emotional differentiation, they seem to be keeping lots of issues in different boxes rather than mixing and matching all. Congress leaders are tied to a set pattern of emotions influenced so much by one family, which is their savior as well as destroyer.
BJP thinks of the next generation, Congress thinks of the next elections.
BJP mostly chooses and looks for statesman, Congress mostly looks for politicians.
BJP believes in ‘actions don’t bring you happiness, but there is no happiness without actions’. GST, Demonetisation etc are a case in point.
BJP translates its nationalism into action gaining global respect, congress denigrating it, and everyone knew it. This is so evident in the defense policy that they followed in during their last tenure where they made India so vulnerable to external security threats.
BJP is very organized party now, an innovative party, almost functioning like a corporate, Congress still has a lot of adhocism in it.
Incidentally, Congress has a lot of talent-Dr Tharoor, Jairam Ramesh, Piyroda, Chidambaram, Sibal to name a few; BJP lags behind in this sphere.