Cambridge Audio Azur 840 A Integrated opinions?

Hi. I'm currently considering a Cambridge Audio 840A integrated amp at a local audio boutique. The unit retails for $1,600.00 (almost everywhere), but the store has one left for half-price. It offers 120 wpc into 8 ohms, and 200 wpc into 4. It uses a new patented amp class called "Class XD", which means it operates at a pure class A level while having the efficiency of a class AB. Listening to the thing in the "sound chamber" in the store was stunning, but I'm not sure how much is due to the 640C CD player running through it. To help me make a decision, I took a 20 year old Denon DCD-1500 CD player & the owner let me hook it up. Not nearly as impressive. I have an Arcam Alpha 8SE CD/HDCD player that I use daily, and I should take it down to the store & listen, but I'm afraid to truck it around town. I have KEF Reference 103/4 loudspeakers. I will be replacing an Adcom GFA-555 and Adcom GTP-500II pre-amp if I pull the trigger. Any thoughts???