Middling lawn approx 200m2, I have a self propelled rotary petrol Hayter 20" with a roller. It's not really up to the job tho. It would be if I had a picture perfect flat bowling green but unfortunately my lawn is sloping, full of weeds, holes, lumps & bumps plus a long strip on a slant in front of my house . It clogs up really easy when the grass gets too long as well or is even slightly damp (much swearing & muttering with vile threats then ensues). Re another thread hot summer 2010, this is also one reason I hate hot summers.
We should have gone for the bigger size & a Honda but it was too expensive (this one was nearly £400! Good grief what was I thinking!). Ah well next lottery win maybe. I would recommend a self propelled petrol though espec if your lawn slopes, but I am not sure re pros & cons between rotary & cylinder. I think proper lawn people would always recommend cylinder. Mine is anything but proper tho