George,

Here's what the test returned on average fopr 100,000 interations;

Do CASE: 0.6310
One Liner: 0.3900
IFs: 0.5110

One interesting side note is that the times were exactly the same for every run.

I still say that the IF and the DO CASE are equally as readable and understandable but teh one liner is complex and confusing requiring carefull attention to suss out exactly what it is doing. That is enough of a reason for me to prefer either the do case or the if approach.