My favorite of all time to watch was Connors. A Great player who had no serve speed, but attacked the net relentlessly if the ball wasn't on the baseline.
Conners was a great baseline player. McEnroe was a master serve and volley player. As was Martina Navratilova, (etc)
Top players today dont serve an volley often, unless they are pulled into the net. Today's players are just too good at passing shots.
Sampras was arguably the GOAT until Federer took that title. Nadal could have passed federer but it doesnt look like his body can hold up to his physically draining style of play.
(Sampras and Federer win a lot of games due to their excellent serve, Nadal doesnt have that luxury and wins with heart and effort.)
Martina and Steffi were arguably the best women ever, but now Serena just earned that title. Too bad they they didnt all meet in their prime. I give Serena the edge, she is just physically too strong and overpowering for them (and everyone else).