The Sim Audio W-5 is a very nice amp for the used prices as is the Pass X-250. The Sim is a very fast amp with a nice balanced sound, the Pass has a slightly different sound maybe a little more romantic. If you can find a good deal on an Edge amp they are very clean and fast and slightly clearer than the Pass. I own the X-250 and love the amp in my system and Pass has the best service that I know of especially when you are in need of repairs.
Happy Listening.
Happy Listening.