Driving a tanker is quite different from the other types of driving in a number of significant ways, many of which revolve around your driving skills and the type of tanker. You have 3 major types of tankers...food grade, non-food grade, and bulk solids.
Food grade tankers do not have baffles in them. Baffles are walls, sometimes solid and sometimes with holes in them, which act either to divide the tanker into compartments or to minimize the sloshing of the liquid within the tank.
Because of the health issues involved with keeping a food grade tank clean and sanitized they do not allow baffles inside of them. You can compartmentalize a food tanker, but you can not prevent sloshing with barriers.
A typical food-grade tanker can haul about 48,000 pounds of liquid. You can imagine the forces involved if you were to haul a very thin, heavy liquid, like salt water, which only fills the tank half way before you are maxed out on weight. When you accelerate or hit the brakes the liquid will slosh from front to rear. If you are not gentle it can be very dangerous. For instance, if you are exiting the interstate onto an off ramp with a sharp curve and you hit the brakes pretty hard just before the curve, the liquid will surge forward and give you a huge jolt (hard enough to knock the hat off your head) right in the center of the curve. It could easily cause a rollover or cause you to slide off the ramp if the road is slick. The sloshing can also make shifting much more difficult which takes a bit of time to get used to.
Non-food grade tanks are allowed to have baffles in them to prevent sloshing so this is a bit of an advantage, but I wouldn't call it night and day. Let's call it a little bit better. The trade-off of course is that you are hauling chemicals, often very dangerous ones.
The difference in pay between chemical and food-grade jobs is negligible so I never really could understand why someone would choose to haul dangerous chemicals instead of things like milk, honey, and juice.
You can't mix food-grade with non-food-grade loads in the same tanker. You must haul either one or the other type of product by law. Now of course one company can own both types of tanks and have their drivers switch between them, but honestly I don't know of any companies that do this. They may be out there, but generally a company will specialize in one or the other.
Dry bulk tanks haul things like sugar, flower, and sand. These dry bulk materials require special tanks and air-pump systems in them to unload the product. The difference in pay between the three different types of tanks really is negligible so again it's really a matter of preference.
Now all three types of tanks will require a bit of work from the driver. Often times you will be required to at least hook up hoses from your tanker to the shipper or receiver's tanks. Sometimes you will have a pump installed on your trailer and will be required to pump the product out of your tank into the receiver's tank.
You must also vent your tank which usually just means to open the hatch on top or the tank will collapse as you unload it. Air must be able to fill the space that was occupied by the product, just like if you were dumping out a gallon jug of water.
Most companies pay you a little something...maybe $30-$50 dollars....if you have to pump out your tank. Depending on the type of tanker and product the process can take anywhere from 45 minutes to 2 hours to complete and it really isn't difficult or dangerous.