There is no answer - if your grass is half a mile away from the nearest electrical supply then petrol is better - if your lawn is extensive in size and or you are a lazy person like me then self propelled is better. Of my three mowers I prefer the petrol one - I have to push the electric ones.
A cylinder mower gives a better luxury lawn type of cut but the blades don't like small stones - small stones with a rotary cut are easily managed - the blade may be replaced unlike a cylinder.
Petrol usually costs more to buy and cylinder mowers are more expensive than rotary types.
Ask yourself how long in time you are prepared to spend mowing the grass - how much you can afford - what type of lawn finish do you hope to achieve and then look at the market and decide.
Good luck...
Peccavi, January 2010
