Gentlemen,
I spent a long time debating wether to buy the pipe-pro 304 or the pro 300. I ultimately decided on the pro 300 for a couple of different reasons.
For one, the pipe-pro was more expensive about $2500 more for a couple of fatures that I really dont need. Weld at idle is great but the pipe-pro idles at 1800rpm which is what my pro300 welds at wide open!
The pro 300 idles at 1250rpm. This saves fuel and wear and tear on the motor.
Secondly, the pro 300 has a Cat deisel engine, made by Perkins, whom many people I know consider to be the best in the world and far superior to the Kubota in the pipe pros.
If I worked in shops or near other sources of electric, my decision may well have been different. Being able to dis-engage the engine and plug the machine in would be a great feature but I've never been in a situation where this would be benificial.
Hope this helps.
Beracah