Recommendation for Class-A integrated amp

Luxman L-595A Special Edition is worth consideration as well: http://www.luxman.com/product/detail.php?id=38

Heads up that I'm a Luxman dealer.

Truly depends on the speaker pairing.  What are your speakers?

I did think about the Luxman L595ASE, but can't find much internal difference to justify the higher cost, so any information about the internal improvement would be very helpful.

The amp will be dual used in main system that has Abyss AB-1266 Phi TC, and the secondary system has Ascend tower with RAAL option.

Of those choices I'd lean towards the Pass or Luxman.  The Sugden would be a better fit with higher impedance speakers that aren't 25W minimum like yours.  Your Ascends drop to 4 ohms and I'd think the Pass and Luxman would cooperate very well with that.