You are correct that the older gas tractors are easier to work on, and they are also better for frequent starts, and short time operation. A novice can repair many problems which may arise without specialized tools or knowhow. Again, the biggest advantage is minimal cash outlay to get started, and the ability to recover that if you decide its not the right equipment for you. A 3/4 ton pickup and car-hauler type trailer would be needed for hauling such a rig from job to job. That may force you to upgrade your hauling ability and that is the only drawback I can think of.