The speed is quite terrible. It has an even worse acceleration so I don't think you'll ever discover its top speed. I don't think that you'll drive this vehicle a lot so don't worry a lot about the speed. Even if you do or will drive it, I doubt that you will use it as a getaway car.
Handling is just as good as the speed. As the ambulance is a large vehicle, it is quite hard to handle at top speed (which is still slow) and sharp turns. You'll need to be very careful with the handling because it is very annoying when you spin out of control.
The damage is a whole new thing altogether. It is a very tough vehicle and it can take a lot more damage then just an ordinary car. This is definitely the best aspect of the vehicle. You can rely on the damage I think, because you can easily tell how much more damage the car can take just by looking at it.
Ambulances can be found at the hospital. Just outside the hospital, in the car park, you will always find an ambulance parked.
It appears in The Getaway: Black Monday as well.