Traditional BCD Style
The traditional style jacket offers a snug fit which hugs the diver at the sides as well, providing inflation at the rear and sides ensuring the diver remains in a heads up position comfortable at the surface. Ladies BCD's offer better comfort and fit for the female diver, the back section of the jacket is often shorter in length and the weight systems are usually integrated for added comfort
Wing Style BCD
The wing style puts the inflation cell on the divers back and many divers feel this is exactly where they want their buoyancy to be underwater. Wings offer a more streamlined appearance and are less cluttered at the sides and front. This style of BCD can also be modular in that it can grow with the diver and can later be adapted with a bigger buoyancy cell if required. There is a belief that a wing can have a tendency to tip a diver forward at the surface but this is less true with the new wings as they have compensating weight pockets on the rear which negate this effect.
Some BCDs both jacket style and wings come with the weight system integrated into the pocket areas. This can be beneficial as the jacket has been designed for the weight to be carried in this way as opposed to wearing a normal weight belt. It should be considered that this does make the jacket heavier on exits if the pouches are not removed first and if they are not secured properly pre dive then they can become dislodged. In the event of an emergency the pouches can be dumped easily and quickly.
Power Inflate V Standard Inflate
Some designs have a power inflate option operated by a lever on the side of the jacket. Jackets from Mares and Aqualung offer this option with the I3 and Airtrim range. This will likely be a different type or option than that which you learned to dive with. Many divers find the power inflate system easier to operate and easier to adjust. The standard inflate options are the type where the inflator hose comes over your left shoulder and the inflate button is at the end of this hose, this is a proven design that works. In the end it comes down to personal choice of the diver.
Modern BCD's offer the diver plenty of lift if they are being used for the type of diving they were designed for. If you start adding extra cylinders for deeper diving or twin cylinders then you may adversely effect the amount of lift you have. It is vitally important and prudent to carry out a buoyancy check at the start of your dive to ensure you are weighted correctly for the environment and conditions in which you will dive.