I have quite a bit of lawn to mow so a few years ago I bought a Toro commercial model with a 60" deck that is fantastic. It is much faster, more powerful (can handle thick or wet grass easily) and more agile than a traditional riding mower. Parts, such as a new belt, are expensive but overall this has been a great investment.
I needed to make a change because I was spending way too much time mowing on an older, traditional riding mower.