Dinghies come in two flavors, hard and inflatable. When you look at a popular dinghy dock, it would appear that inflatable dinghies dominate the scene. Each type of dinghy has its advantages and disadvantages, it's just a matter of figuring out which advantages are important to you and which disadvantages you can live with. While inflatables are very popular, you should still decide for yourself what your needs are before you buy an inflatable like everyone else.
The major points of difference between the two camps have to deal with stability and propulsion.
Hard dinghies are easier to propel through the water, but are much more tender.
Inflatable dinghies are extremely stable, but are not as easy to propel through the water.
Hard dinghies are easily rowed in light weather, and can still be rowed with strenuous effort in heavy weather. Inflatable dinghies on the other hand can only be rowed when there is no wind present. If there is any wind, you may find it impossible to row towards weather. To combat this pitfall, inflatables are propelled via outboard motor.
Stability is the other great difference between the two camps. Hard dinghies are very tender and can tip if care is not taken when boarding or standing. Inflatable dinghies are extremely stable, allowing you to stand up and walk around on them without any fear of capsizing. If you stood on the gunwale of a rigid dinghy, the boat would tip over and swamp. Doing the same on an inflatable dinghy would be totally acceptable. You could easily stand on the gunwale and be fully supported by the inner tube's volume of air.
There are some other minor differences between the two that also play an important role in deciding which to use, these deal with longevity. Inflatable dinghies will be eaten up by the sun and begin to leak out air after a few years of use. Sand is another nuisance in inflatables, it will work its way into the folds in the fabric and chafe small pinholes in hard to repair areas. Hard dinghies on the other hand will hold up quite well in the sun and will not be destroyed by the ingress of sand. Hard dinghies will also do very well with frequent beach landings, though the bottom paint will suffer as well.
Lastly, outboard motors on dinghies are a frequent topic of complaint from all of my cruising friends. At some point, repairs or replacement of their outboard will stir up furious emotions from within them.
Finally, storage is a factor when it comes to dinghies. Soft bottom inflatables, which are not as popular as RIBs (Rigid Inflatable Boats), can be deflated and rolled up. This allows them to be stored tucked away in a lazarette when underway. RIBs and hard dinghies need to be stored somewhere on the boat, and they do take up a considerable amount of space. Some popular storage areas are in davits on the stern, or overturned on the deck.
When you are looking for a dinghy to complement your cruising boat, look at the pros and cons of each. If you are torn between inflatable or hard, you can use this simple question as a tie breaker:
Do you want to stress about outboards and sand or do you want to enjoy the beach?