[TenTec] The QSK of QSK

[Bill Tippett]

 >I should be able to hear a station calling someone else in between
dits, AND know it's the DX not another station trying for him
just like me?

You don't need to "hear between the dits" to do this.  I've used
foot switches exclusively for both CW and SSB many years in both
contests and low band DX-ing.  I've learned to simply let up my 
foot  between CW letters while sending my call in low band pileups (since
effective DX-ing speeds are fairly low 18-25 WPM on 80/160).  If
speeds are faster, I may do it between words (i.e. my callsigns).
PTT does not mean that you only engage it at the beginning and end
of an entire calling sequence.  It is very easy to make/break
between words or phrases on SSB and between characters or words on
CW (depending on the speed).

QSK may be nice for high-speed rag-chewing but it is certainly
not a necessity for contests or DX-ing.  DXCC 312-160m, 339-80m,
17 major DX contest wins including 6 USA SOSB10 alltime records
since 1999.  All using PTT except for the last one (2003 CQ WW CW)
which used Orion in semi break-in mode...prior to the recent PTT
firmware update.  ;-)

73,  Bill  W4ZV