These two seem to be pretty comparable, but the Craftsman is ~$400 cheaper. Is there a real difference between the two, or would I be paying $400 for the JD brand name? I read on the Sears website reviews that the YT4000 might have problems with hills. Other reviewers disagree. My yard is basically a big hill (maybe 5- 10 degree slope, and is very bumpy with ruts, about an acre. All I'll be doing is mowing (slowly due to the rough nature of my lawn).