I've got over a quarter-mile of barbwire fence to install in Northeast Oklahoma and I'm not real keen on using a manual pounder to drive some 200 T-posts into that rocky ground. Two companies make pneumatic post drivers that should run off about any 5 HP or larger air compressor: 1. The Rohrer Man-Saver T-Post Driver, which comes in several models and starts at $450. 2. Rhino Air Post Drivers. These come in various sizes and start at around $900, but the necessary control valve and filter/oiler would add another $500 to any of them. Obviously, I'm leaning toward the less-expensive Rohrer. Has anyone had any experience with either of those or any other pneumatic post driver?