Diving Guardalavaca was a nice experience. They have a great wall with really nice tunnels. Also nice to see is a grave yard of Russian military equipment that includes tanks underwater. To see the Russian tanks the conditions must be optimal due to the sand around.
Some shallow dives are not that great due to some white corals and the lack of marine live and many divers skip the second dive every day. Also the fish population is decreasing in an alarming rate and a company called Gaviota tours have an activity for reef fishing in the area that is not helping and the funny part is that they do diving excursions too.