For what its worth, here is my take on Senna.
He had success in karting but never beat Terry Fullerton. He had success in British F3, winning the championship in 1983, but pretty much either won or crashed out, particularly in the second part of the season. This style would characterise his F1 career. There had been uncompromising F1 drivers, like Mario Andretti and others that came after him like Schumacher, but Senna had more than fearlessness of Mario or arrogance of Michael.
He was undoubtedly a quick driver, but it was his uncompromising and religious self belief that set him apart. This confidence manifested itself on the circuit. Fellow competitors in F1 soon discovered that if you got in his way, or attempted to block a passing manoeuvre, he would rather have an accident than allow anyone to get the better of him. I don't think it was the same style of calculated bullying and blatant cheating that bought Schumacher his world championships, but a simple belief that he was the best, and deserved to win at any cost. His attitude did not endear him to the other drivers, and most significantly to his team mates. It polarised attitudes towards him by the press and the general public. Race fans either loved him or hated him, it was almost impossible to be neutral.
Love him or hate him, the Senna movie is worth a watch, but I wouldn't walk a mile...