A very broad question. What do you mean by: "best stroke"?
I see people mention power, some say finesse etc. No player is complete, but some come close. I see lots of old timers being mentioned, from what I see on youtube, these guys couldn`t hold a candle, compared to todays players.
Judging by who wins, it`s obvious that the most complete players are guys like SVB, Mika Immonen, Thorsten Hohmann, Jayson Shaw and Niels Feijen.
They play great straight pool and rotation games, break good and shoot very straight, have good creativity and consistency.
Guys like Efren Reyes I`m sorry to say dont have a great stroke, but he is extremely creative and knows the rails better than anyone.
Bustamante has his own style, but mechanically he is a train wreck.
Earl Strickland is very enjoyable to watch, I like his gutsy way of playing and his long stroke is great fun to watch, but he`s a terrible ambassador for the sport, due to his temprament.
My personal favourite is Mika Immonen, he`s got just the right amount of flair to he`s play, combined with great precision and nice mechanics.
The fearlessness and precision of Jayson Shaw is also great to watch.
I know I have left out several well known players, I just mentined the ones I have watched enough to have an opinion about.