First of all let me tell you that the bad reviews you read are just from angry people that do not know how to enjoy life.
Flight to San Juan was the only horrible experience I had and that was not the airlines fault. It was the idiots on the flight that thought that everyone was interested in their conversation, their card game or their singing voice (if it could be called that). So sleep was not an option on our red eye flight. I did not let this spoil my vacation, just bit my tongue and waiting for the fun to begin.
Our taxi to old San Juan was quick and painless, we got dropped off at pier 4 and walked across the street as instructed by a nice guy who was directing people off the previous cruise. He informed us that there was a lady that would watch your bags for $2 a bag until you loaded, so there we went. She was great, gave us a map and told us where and when the free trolly's ran. We walked down the street to the Sheraton, where my husband got us a free breakfast, not on purpose, we just went to the wrong area to eat and the guy told us to go ahead and eat with them, we were in San Juan and on vacation. From there we went to the trolley, road the one that takes you to the forts, a beautiful sight. Old San Juan is just that old, but there is beauty along with the cracks.