Flash,
He won about 14 majors, over 120 tournaments plus he won head to head tours for the World Championship of tennis over some of the greatest players in tennis history.
Like I wrote in the previous paragraph, many of these players in the head to head tours were against some of the best players in the history of tennis. Gonzalez faced Lew Hoad, Frank Sedgman, Ken Rosewall, Pancho Segura, Cooper, Anderson, Gimeno, Olmedo, Kramer and Trabert.
Gonzalez won all these tours but his first one against Kramer, when Gonzalez was very young. Gonzalez eventually overtook Kramer and became the number one player in the world.
The tours were very long. The players would play at one site and often drive themselves to play the next day at another site. For example Gonzalez beat Hoad 51 to 36, Sedgman 30 to 20 (around that anyway), Segura by about the same as Sedgman, Rosewall 50 to 26, Trabert 74 to 27 among his many tours. He won an incredible tour against Rosewall, Olmedo and Segura by a combined match score of 49 to 8 defeating Rosewall by a great score fo 15 to 4. Rosewall was to become 26 that year and he was probably in his prime.
Remember that these tours were to determine the World Champion of Tennis therefore they were more important than the majors for the pros. I spoke to a member of the Gonzalez family and this person assures me that Pancho Gonzalez's main goal was to win the tours to keep his title. In that way tennis at that point was somewhat like boxing has been over the years. Remember if he did not win the tours the ex champion was considered a has been and his earning potential goes down tremendously.
How do you value this tours? It's possible that you could value these tours as the same as a few classic Open Majors.
So his record is 14 majors, a ton of tours won, over 120 tournaments won. He lasted into the Open Era and in the Open Era he was able to defeat Laver, Newcombe, Ashe, Rosewall, Borg, Connors, Roche. This is after he turned forty years old.
As far as playing style is concerned, Gonzalez had perhaps the greatest single weapon in the history of tennis in his awesome serve. Vic Braden, the renown tennis coach does computer analysis on strokes. He wrote in his book Tennis 2000 that he was convinced Gonzalez would serve regularly in the 140 mph range in the earlly 2000's. The difference however is that his motion was so easy that he would be able to serve with great power late in matches. Gonzalez had great footwork and excellent mobility plus an excellent volley. He was also an excellent baseliner with a very strong forehand. His backhand was not as strong as his forehand (as most one handers are) but very good for baseline play and he could hit brilliant shots off both sides.
Here's a video of Gonzalez.
http://www.youtube.com/watch?v=Nd0gJzm_EQY