Do you think its power output is more like the Metcal 5000 [ ~$600] or the PS900 [~$300]?
Tips are ~ AU$17.
With output power of 30W, it's closer to the MX-500. The newer MX-5000 series is supposed to put out 80W. I'm guessing that OK didn't have much incentive for a newer unit until their patent expired. That probably means they didn't figure the demand for an 80 watt unit would justify the production, until they had to compete and got marketing involved.
These units are pretty simple, so I'd expect that if the Thermaltronics unit is solidly built and good quality, it will perform--and endure--just as well as the Metcals, so the choice would really come down to price. I think most people would be more than fine with the 30-40 watt unit. Are the handpieces and tips really interchangeable with the metcal parts?
Dave