I can't remember exactly were I read it but I do remember someone saying that the FSL tubes put out somewhere between 23 and 30 watts when running, no where close to the 40 watts they tell their customers there getting and that statement was supposedly from the tube mfg's website
Good point. And if you dont have a $500 watt reader, you wont really know unless you know a 40W tube should cut 1/4" poplar in one pass..but most dont. Also , even if it does put 40W out the end of the tube -by the time it bounces around the mirrors and through the imported optics you're lucky to get 30W. Good mirrors and optics make a big difference and they're a lot cheaper that stepping up the power on a tube.
Good Technology Without Good Service Will Be Bad Technology