Hi Mdnocum. I'll try my best to put this into words . . .
Impact on Speakers:
I didn't realize how fast my Vandersteens could be until I got the L505u. The front edges of notes spring into the room, and everything seems more lively. Also, the resolution is much better across the sound spectrum. I didn't realize the Vandies could be so detailed in bass, mid, and highs. Never harsh, mind you, only an abundance of the correct musical details.
Impact on Sources:
The analogue front end is least changed. I just notice a more well defined soundstage and better detail. As I stated in another thread, the texture of strings and body of stringed instruments is wonderful.
The digital, which is an inexpensive Oppo, is a mixed bag with the Luxman. Initially, the amplifier revealed the shortcomings of the Oppo to me: some blurred imaging, undefined bass, and difficulty with complex music. While I still believe this to be true, I've also had some very enjoyable listening experiences with small combo jazz and acoustic music. I can certainly see that a better CD player will bring great returns in digital playback. That's probably going to be my next upgrade.
I hope this helps. It's hard to describe these things. I know that I'm enjoying music for music's sake from this amplifier, and many nights I lose track of the time while the disks spin and the meters dance!