Many of us still call rotary mowers “hover” mowers, but they don’t all hover (especially if you’re sitting on them). Their key feature is that the blade rotates in a circular motion above the grass – lopping off the tops. Cylinder mowers are the more traditional type with blades moving in a “rolling” motion. Their cutting action is very different: the grass is caught between the blades and a fixed plate in a scissor motion.
Pros and cons of each lawnmower type
Cylinder mowers are more likely to have a grass box, but are not good at cutting long grass. Struggling through long grass on a hot day with an old cylinder mower has been depicted in many a cartoon over the years. Today’s mowers are better, but there is still some truth in it. If you depend on a cylinder mower, you may have to cut the grass more often so that it doesn’t exceed the mower’s capabilities.
The quality of the cut also varies. On a well-cared for lawn, a cylinder mower provides a gentle and even cut. Because the motion is all in one direction, they leave the lawn in neat strips (like those here https://thelawnman.co.uk/a-gallery-of-beautiful-lawns/). In contrast, rotary mowers can leave a difficult lawn with tufts at all heights.
On large high quality lawns, cylinder mowers make more sense, but on typical lawns, it is the quality of the mower that matters most and not its underlying technology.
Things to look for in a mower
A mower needs three main things: a motor that’s up to the job, sharp blades at all times, and access to quality spares. In order to ensure those three, there is a fourth – easy maintenance. Cheaper mowers often carry brands of convenience so when you need spares, that’s a problem. If you have a well-known brand like Mountfield parts are easy to locate (for example https://www.diyspareparts.com/parts/mountfield/).
As a rule, cylinder mowers are more difficult to service. In particular, it is hard to remove the blades for sharpening and then replace them correctly. The angle of the blades and their sharpened edges, have a major impact on performance.
You also need a blade height adjuster. Grass length is critical for the health of the lawn. What you can cut depends on your lawn’s existing height and weather conditions.