I bought a lawn business 2 years ago. A few things to look our for.
1. Equipment.. I looked at it and it looked good then after buying it I went and bough all new stuff as it was all junk and broken, even after the mechanic fixed it.
2. Make sure you look at the books and see how much business and money it brings. Find out if there grinning in anything off the books to. The guy I bough my business from had trained all his customers to pay cash. I had to change that.
3.Make sure that the company is not a lo baller. Mine was and all the lawns I have are so cheap, I don't know how he was making money. I had to up prices the next year. Its hard to tell that on paper, but if you can get them to show you the yards before hand and see if they should be higher.