Cuba has its pros and cons. Varadero beach is one of the most beautiful beaches in the world and several of the newer resorts compare favorably with those you would find in other locations. The entertainment and customer service can be very good, the food not-so-much, but you won't starve and who wants to gain weight on vacation? Save the calories for the delicious rum-based drinks (and the fabulous coffee). The problem is that buildings in Cuba don't tend to age well, especially by the ocean. Bad storms and humidity take their toll and trade restrictions make repairs difficult. So, book a newly built resort, lower you expectations a bit and book at least 1 star class higher than you would elsewhere.
On the plus side, the prices are great. All inclusive vacations are cheaper than in most locations and some of the world's best rum and cigars are a steal. I'm not a smoker but I must say that I enjoy the smell of a good cigar wafting through the warm night air (although there are more non-smoking areas now then when I first went in 2008).
The local markets are great for souvenir shopping including some beautiful jewelry. The vendors aren't overly pushy like I've seen in some other Carribean countries although they will try to lure you in with some good-natured banter. Most young people in the tourist areas speak excellent English thanks to Cuba's free education system.
Havana is a bit run-down in spots but you can see that it was once beautiful and people have done their best to protect the facades of buildings in the hope that they will someday be able to restore them. You can see why it is a Unesco world heritage site. Some restoration work has begun in recent years and will hopefully bring back its former glory. The old cars are definitely worth seeing and many are used for tours and taxis.
So yes, it's worth seeing. Have a mojito, relax your standards a bit and Enjoy!