I own the KI Pearl Lite and very satisfied with it. But I prefer the "warm" Marantz-sound over the "analytical sound" of many players.
IMO, 8004 and SA KI Pearl Lite are at least 98% the same.
When I connect my KI Pearl Lite with USB-port from my laptop, he gives "SA KI Pearl Lite - 8003" as soundcard name!
I ordered the 8003, but after my order was placed they figured out that all "8003s" were already sold, so I got a very interesting reduction at the price (if i bought the KI Pearl Lite).
So I finally bought the KI Pearl Lite (for about 250£ more than the PM/SA8003 combi) with B&W685's. Sounds stellar in my small hobbyroom.
The sound of the USB Marantz <-> USB Laptop is very good and detailed (tested e.g. Band On The Run - check HDtracks). I was thinking of buying an external dac (dacmagic or more expensive the Benchmark dac usb), but have no idea if it's worth the money? Because it sounds already good to me without an external dac.