Ride on mower advice .

Wonder if anyone can advise us on which 4wd ride on mower we could buy to help us cope with the slopes and amount of grass we have to cut here on a regular basis. I have been looking at the Husqvarna and the Stiga park mowers but perhaps someone can suggest a different mower that can do the job. We have about 2 acres of grass to cut but our main problem is the steepness of the terrain. At the moment I am using a Honda HRX 537 self propelled mower with a 21 inch cut and it takes me a full day to cut all the grass. The slopes range from 20 to 30 degrees. I don't expect the ride on to do all the work as some parts are too steep but if it would take the bulk of the work I would be more than pleased. Hope someone maybe has the same type of problem and could suggest a mower that could save us a heap of time. Thanks in advance... K