Do yourself a favor and get one with at least 6 hp.
I primarily mow with a Lazer Z but use a 22" to do steep ditches and "tight spots".
My old 3.5 hp MTD finally bit the dirt and I needed a replacement pronto..but I could not justify spending $700 (or more) as I do not use it that much. So I ran into Lowes and grabbed a YardMachine w/ a 6 hp B&S on it for $214. It is not self-propelled but that was not necessary for what I use it for. It has been great and cuts stuff that would choke the 3.5 hp engine. It also starts on the first yank...every time...and runs real smooth too.
If a 22" is all that you use for your business then listen to the guys who are recommending the Honda. Or at least buy the best machine that you can afford. But if you need a "quick fix" to tide you over until you can upgrade at least get one that has a 6 hp engine...and easily adjustable wheels.