In this article, you will not get a definite answer "what to choose MNC's Or Startup Company". See both are the different scenario but both have their own value. It totally depends on your personality which is suitable for you. In MNC you find a structured format of doing work, large team members and Job security because in MNC's there are many stakeholders in it. But in a Startup company, there is nothing like that plus you will have work extra hours on work deadlines or clients demos there is no job security in a startup.
But if you want a fast growth in life Or want to learn how to run an organization for your own Startup then Startup company is best but be ready for the struggle, you will have live below your means. get some stress about work & clients etc. The things you will learn in a startup company is priceless, Nobody will teach you in MNC's if you dare to learn these inside your MNC's they will feel insecure try to throw you out because politics are much in MNC's and you will be just a small part of large company, there will be job security in MNC's
It's wrong to say that startup is best or MNC's is not good OR vice versa. Because there are many companies like IBM, GOOGLE, Other tech giant company and not only Tech gaint there are other many company which provide huge growth and another facility. But if you want to be your own boss or want to make your own brand that gives competition to MNC's Or have your idea/dream then should choose Startup.
Now its totally depend on you which one to choose A Startup Or MNC's. It's Your Choice.