Up board- deep and superlative syllabus. Toughest amongst all. Language hindi and english is specifically tougher . Maths is 3x tougher.( Talking untill 2013)
Cbse- to the point course. Best for competetive exams as questions are formed from ncert books.
CISCE- English is the psalm and gist of this board. Syllabus is robust, with lacunae in deep understanding.
More or less permanent residents of Uttar pradesh shall opt for U.P board.
To note- major key posts are occupied by illeterate or poorly literate people in India. So board does not count that much