I can tell you this. TV cannot do Tanner's serve justice. It remains to this day, the most awe-inspiring athletic movement I've ever seen. No exaggeration.
If you made a robot who's only purpose was to hit a serve, it would look like Tanner.
The last thing you saw was him lining up towards the box. Then the blur of the figure eight of the racquet, blinding blur, while the toss seemed to come to the exact spot that his entire body was unwinding to at the perfect instaneous moment. On TV, it just looks a bit quirky and fast. In real life, it is perfect timing, perfect effiency....inhuman.
I don't necessarily think it was the most effective serve of all-time, but the motion was the most impressive of all-time!
I've seen Sampras, Goran, Newcombe, Ashe, Lendl, Becker, McEnroe and I can truly say the most stunning serve I've ever seen was Roscoe Tanner's serve. I'm not saying Tanner's serve is the best but when I first saw it, WOWWWWWWWWWWW!