One of the most important decisions you will need to make when looking to purchase a wheelchair accessible vehicle is whether you want a manual or an automatic gearbox. If you are going to do the driving it will depend largely on what your physical capacities and limitations are. It is more common to have an automatic transmission in vehicles driven by the wheelchair user as this allows more space for other adaptations that may be required. While driving with an automatic gearbox is generally more relaxed if you want to enjoy the greater control and emotion that manual gear changes can offer, you should talk with a professional converter who will be able to determine if it is possible.
Wheelchair accessible vehicles where the wheelchair user travels as a passenger are available with both manual and automatic gearboxes. Vehicles with manual transmissions are usually less expensive than a comparable vehicle with an automatic transmission. Also, as manual gearboxes are far less complicated than automatic ones, if something goes wrong they are much cheaper and easier to repair. They also weigh less which can translate to savings in fuel consumption.
Automatic transmissions certainly make driving easier, but, some would argue, not so much fun. However, for about town driving with lots of starting and stopping an automatic is the way to go. Also, if you live in a town with steep inclines those tricky hill starts are avoided with an automatic transmission. Additionally, as the vehicle is always in the correct gear with an automatic gearbox this can reduce wear and tear on the transmission and can also increase the miles you get per gallon.
So, which is better for a wheelchair accessible vehicle transmission, manual or automatic? It is really a personal choice. Ask the person who will be doing most of the driving which they would feel more comfortable with.