A regular, or manual-push, lawn mower requires physical labor to drive it forward. In contrast, a self-propelled lawn mower pushes itself along, requiring little human exertion besides guiding it left or right. Self-propelled mowers come in either front-wheel-drive or rear-wheel-drive models. Front-wheel-drives are preferable in situations where you need to turn frequently, since you can lift the wheels off the ground without having to stop and restart the lawnmower. Rear-wheel drives are better for cutting grass on hills and sloping areas.
Regular lawn mowers are lightweight, ranging from 16 to 32 lbs., compared with self-propelled mowers, which can weigh from 50 to 100 lbs. Regular lawn mowers are also lower in price, because they don't have the self-propelling feature. The cost of continued ownership for a regular lawn mower is also significantly lower than for a self-propelled model, as the simplicity of its design makes it less likely to break down.
Some people enjoy the exercise benefits of pushing a lawnmower, while for others the lack of exertion makes a self-propelled mower desirable. Hills and inclines require even more energy, and for those who either don't want this challenge -- or are physically unable to endure it -- a self-propelled mower may be a better choice. However, if there is ever a problem with the self-propelling feature that cannot be repaired, pushing this heavy contraption on a regular basis will be burdensome, particularly for anyone who chose it specifically to avoid physical exertion.
Regular lawn mowers are better suited for small, level lawns, since there's not a lot of square footage to cut, but self-propelled mowers are more advantageous for medium to large lawns, and hilly or sloping areas. The self-propelling action also reduces the amount of time it takes to cut your grass. However, because some of its power is expended on the self-propelling function, there's less power for cutting tall grass, which makes it less effective for this purpose than a regular lawn mower.