Big City vs. Small Town
Very true. La Habana, being the biggest city, has more choices, options and possibilities. Better places to eat, drink and hang out. Obvioulsy, since the population is larger, there are way more girls to choose from. Like anywhere else, big city people are a little wiser, a little cynical, ready and willing to wheel and deal to get the most that they can. You'll have no problems with girls because if the one you meet comes off as greedy and opportunist, you can just walk away from her and a sweet one will come along in a moment.
In a smaller town, word that a 'turista' has arrived spreads like wildfire. Especially a single man, traveling alone. Remember that most people in Cuba do not travel. Mostly they cannot afford it and they have too many restrictions in their travel requests with their government. Even internally. When a 'turista' arrives and asks a local girl out, it's like she's won the lottery. She'll be sweet and accommodating hoping that she'll be taken to a nice restaurant, maybe get some nice gifts and will not even think to reject the idea of sex. Whatever you donate is fine with her. First of all remember, it is a latino/machista man's world. The fact that a foreign tourist picked out a certain girl from all the others brings the cache that: "he picked me so I must be prettier and sexier than the others". It is a compliment to her. Living in North America with all the DragonLadies conditions us to forget that most other countries are 'Men's World' and women are very feminine and submissive. I have had this conversation many times with Cuban nationals, men and women, who always confirm this. Luckily, my serviceable Spanish allows me a bit more insight than most.
So, there is a bit of the Big City vs. Small Town in Cuba scenario. You'll have luck with the Chicas wherever you go in Cuba. It's just a choice wether you prefer a megalopolis (Santiago is also of respectable size) or a sleepy, small town.