I took the plunge & purchased the Cambridge Audio 840C for my bedroom system (see above 12/28/06 post). It is broken in and I will give my findings. But first, the 840c is connected to my Portal Audio Panache integrated amp by way of a Signal Cable Silver Resolution RCA interconnect (3 ft.). Kimber Kable 8TC speaker cable connect to a pair of Paradigm Studio 20, V.3 bookshelf speakers.
Initially, I did some comparisons to the DVD/CD player it will replace, the California Audio Labs DVD-2500. Then I listened to it alone for an extended period. I preferred the 840C's sound in more respects but the CAL exibited more bass weight & an overall more full bodied sound. That said, the 840C is not far behind in those respects. Even though the 840C is ever so slightly leaner than the CAL the adjectives to describe it's sound are detailed, musical, punchy & open! What you expect from solid state.
The clincher for me is the Anagram Technologies 24/384 upsampler. The detail of the bass guitar is more apparent. I can hear more of the plucking of the string without the loss of tightness & depth. I've never heard the bass like this before. Even after buying & listening to many CD players including the CAL, Cary 308, Classe CD-10 (most musical), MHZS CD66 (Tube), Cambridge Audio 640C, V.2, Meridian 507 (All things equal with concern to cables, amp, etc.) Rock 'n Roll, which I like most, sounds great on the 840C.
I guess there is something to say about the newer upsampling technology.
One more thing to note: Cambridge Audio is listing a 740C CD player on their site. I see it has the Wolfson 8740 DAC in it, like their 640C series. The 840C has the Analog Devices AD1955 DAC. When I owned the 640C, V.2 I remember it having a warmer tonal quality than the 840C but not nearly the detail. I haven't seen the 740C available commercially nor have I heard it but it may be a consideration for those who like the 640C.
As for now, the 840C is staying put in my bedroom system. For the price, it is a great sounding machine that gives me overall tonal balance and, like many high-end machines, displays the sound exactly the way it is on the CD, good or bad.