Well, back in Senna's heyday, I was still in Junior High and that was when I first became aware of F1. I remember staying up late at night to catch the F1 races on ESPN (the only time they broadcast them back then).
My first memory of being aware of Senna was when he was doing a lap to qualify for his starting position. He had the best time so far, until a slower driver doing practice laps didn't let him pass and slowed down his time. I remember the camera being inside his car and seeing him raise his fist in the "I'm going to beat the hell out of you as soon as I finish this lap" manner to the other driver. I can remember thinking that this Senna guy had some balls.
I remember staying up at weird hours of the night watching the races, and being truly amazed at Senna's skill. When Senna raced, he was truly a cut above the other drivers on the field and I honestly believed that he was the best that ever was. Senna was my favorite driver, and I wanted to see that rivalry he had with Alain Prost. Senna, Prost, (Nigel) Mansell... those were the big name drivers I cared about.
I heard about Senna's death the day after it happened. I believed it was a 10 second blurb on the news. I was in SHOCK. To me, he was the best. How could this happen to SENNA? I suppose it is the same feeling that the previous generation had when Jim Clark died, or more recently, when Dale Earnhardt passed away. These guys weren't just driver's, they were deities. In regards to Senna, what was worst, was the utterly senseless manner in which he died. If you don't know, the big controversy was that, at that time, in order to make things more competitive for the less well funded teams, F1 outlawed some safety mechanisms in regards to braking and traction control. Alot of people believed that if Senna had been allowed to use these things on his car, he would have lived.
After Senna's death, Formula 1 meant little to me. After what happened, I really didn't want to watch it anymore. The driver's who tried to assume Senna or Prost's place were pale immitators (that is until Schumacher came along). The fact that was brought home to me is that Formula 1 racing is the deadliest sport period. I guess the post is a little long winded, but to answer your original question is "Yes, he was THAT GOOD."