I have played with this machine for a while now, and found that it is the best machine in it's class for aluminum tig. The pulse feature is great for stainless or light steel. I have played with the pulse mode on aluminum and found it to be a bit of too much trial and error. As for the frequency adjustment and A/C balance, these features will make this machine worth the money. As for setting up the machine, if you are doing filet welds on aluminum, use a higher frequency. (I usually standardize on around 200 Hz.) this will help to direct the arc straight off of the tungsten. (note, using a 2%ceriated tungsten works best here, sharpened to a modified point. i.e. sharpen as a thoriated tungsten and touch off the point to a flat about .025 or .035 accross). If you are working on outside corners, use a lower frequency, i.e. 30 Hz to provide a softer arc. As for the wave balance, 50% is usually ideal unless the plate is really dirty, and you need the cleaning of an unbalanced wave.
I hope this helps, and good choice on the machine.
Sparx
http://www.millerwelds.com/education/tech_articles/articles11.php
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