Rick, I have to agree with ZL1BBW, true QSK can only really work if you have a very wide frequency split or with remote transmitters (as used in the past commercially).
The expectation is that you can easily hear QRM, or when the station you are working wants to bring something to your attention. With my K4D on QSK you can "sense" a carrier between dots at 30 wpm, but it's nowhere near as nice to use QSK as it is with a short delay where you can hear between words.
Also, you mentioned DSP noise reduction. On CW I find being able to adjust the bandwidth "mid QSO" by simply turning a knob is far more effective than noise reduction, which tends to work better in wider bandwidths such as on SSB.
A feature you didn't mention is diversity receive, the K4D does this brilliantly and it is especially easy to turn on/off, just press and hold the "SUB" button and it's instantly there. Using a horizontal antenna as the TX antenna and a vertical as the RX antenna on 40m, the signal will swap between your left and right ear on headphones surprisingly often, with no loss of received signal. Obviously, your mileage may vary depending on available antennas.
Everyone will have their own personal radio choice, the wider the question, the more varied the replies. Unfortunately, it's not easy to really evaluate a radio without having one in your shack for a week or two, which may explain why some hams seem to change radios more often than most...
73 Dave