Interesting...
If your welders like the 300 they will really enjoy upgrading to the 350 or 700. IMO, at least with the one we have here at work, their is an oddity (hard to describe but a un-anticipated delay or pause right when I / you would expect it to transfer) on the transition from high frequency to weld current that drove me crazy the few times I had to use it. Even sent it in for diagnostics for it, they gave it a clean bill of health but it did not fix the oddity. The repair shop claimed we had to use a certain tungsten to get past the oddity, but if we did we are out of proceedire and that is unacceptable to those making the rules. So the 300 sits in the corner collecting dust. They did fix the oddity with the 350 or the 700 (2-350's stacked).
It's always good to hear the little tweeks from guys with experience and pride. I started tig welding with a high freq box on an old Lincoln buzz box... I always said if you can weld with this, you can weld with anything. The new tech is so awesome and user friendly.
I have not had the chance to try the brand new machines, my dealer called me and said the reps were in town and to drop in. They usually bring a semi trailer with all the new gadgets and a BBQ for a couple days but I was just too busy to stop in. We bought a new plasma table last year and our capabilities have expanded greatly so we have been checking out some new welding gear. I chose to miss the welding and fabrication trade show this year too... next year!!!
I will be checking out the 700 now that you have perked my interest. I priced out the 350 but maybe we will just go for the big gun instead.
As far as tungsten goes... when we purchased our 150 we found that pure tungsten (green) just didn't cut it. It had huge problems initiating the arc. Really that was our own fault. We didn't have any 2% thoriated in 1/16 for SS so we tried to use the 100% tungsten. I actually thought the unit had something wrong with it but we got a bit lucky and talked to the right guy at Miller and he set us straight. Never would have thought the tungsten would cause that problem until we changed... fixed right away. No more cheating!!! lol. We make sure we have the correct components for that little rig.
Cheers.... Happy Trails!!!