Nice find! But we don't have any specs on it and too bad they don't ship outside the US ( im from Europe ), i also saw a 25W one for $375 plus shipping ( $150 for me :-X ) at plans-kits.com, 330€ is pretty cheap! Even the 40W one is a good deal for me, $700/450€, i wont find anything near these...
For this price range ? Yes its quite good, the average efficiency for a sealed CO2 laser is around 5 to 8%, so yes a 10% efficiency for this kind of laser and at this price range is quite good. You can have more efficiency with a different mixture of gases and with a flowing gas setup, but you...