The old two stroke Lawn Boys were the best walk behind mowers ever made. I owned two in a 29 year period, each good for roughly fifteen years before the mower deck and drivetrains were shot. The engines still started first pull, every time. The engines were made by Honda.
Those two stroke days are long gone. As other have said, look for features you want, but always make sure it has a Honda engine. The brand name on the mower itself isn't all that important, it's the engine that matters.
I have a Honda-engined TroyBilt self-propelled that I like a lot. It's about five years old now. Starts right up, only needs 15 seconds, tops, to fully warm up and be ready for use.
I secure the kill-switch bar to the handle with a small dog collar when using it. It has a seperate lever to engage/disengage the propulsion, so I can leave it running while clearing debris or opening a gate.
Good mower.
