I'd opt to start a new one. IMO, the pros outweigh the cons by far. This will also give you the opportunity to make your own bids and avoid having the weed out the seller's unprofitables. As far as start-up costs, you may be able to find money in the form of a grant if you can show your business plan as you might be required to do so by a bank when requesting a business loan.
Depending upon how many you will employee, your equipment investment will vary. My personal recommendation, espeically if you are going solo, would be a 60" ZTR and a 32" WB(hydro). Also, when you buy your 2-strokes, please save yourself lots of money and frustration by buying commercial equipment the first time!
I think you could setup a well - equipped new rig (ZTR, WB(hydro), b/p blower, stick edger, string trimmer, 12 - 14 ft. open trailer, TrimmerTrap racks) for around $20,000 not including a truck to pull it with. That would ideally suit a solo operator, IMO.
Of course, I don't know your budget, but if I had the money, I'd have bought an enclosed trailer and at least a 3/4 ton truck to pull it. It would be really nice when it rains and would eliminate having to load up before heading out for the day and unloading when you come home.
That's all I can think of for now. But I'm sure you'll get lots of advice from others on the site.
