I have, in my 15 minute audition at a local hifi shop, the WA5 (and by parity of reasoning, the WA5-LE) is in a different league from the Studio Six with the right tube combination. I felt it sounded closed-in and lacked exquisite details in the nuances which the WA5 delivers in spades. The WA5 sounded warmer and was more 'delicate'. The Studio Six was more solid statey. Might be a bit of an unfair comparison because the Studio Six may also sound better with upgraded tubes. +1 If you buy Woo amps you better be aware of this. The WA5 stock tubes I had were bottom of the line Shuguang 300Bs and 5U4Gs with a horribly microphonic GE 6SN7. Some say (jokingly) that Woo includes these tubes just to let you know the amp works. I understand why Woo does this though - a company cannot give any warranty on NOS tubes and unfortunately for the tubes Woo selects for most of its amps, NOS vintage tubes sound much better than modern production ones. It has to balance reliability with reasonably decent sound. But I agree with DG that Woo should put in some top end NOS tubes in its amps during meets.