Okay, this post will do nothing to help you out in your quest, but, as I am in the same boat and it will bump your thread I'll post anyways.
I have spent endless hours researching the Vista Hcx and GPSMAP 60Csx. I have concluded that they are, for "all intents and purposes" pretty similar with the exception of the different button layout and antenna. I have also concluded, after reading and posting here, that even if I clip the Vista HCx onto my chest strap or my belt when I run that it will still get good reception of although it does not have the helix antenna.
That pretty much solved my dilemma... if I can still get reception with it on the belt or strap I'm buying the Vista HCx. For me, I was not concerned about the $80-100 increase in price, I just wanted the better of the two units that was at the same time versatile (bike, run, hike, geocache-- already have car GPS so don't need it for that) but it seems they are quite similar. Besides, the Vista HCx will fit better onto my handlebars and running belt.
I also thought about the buttons (no store close enough to make it practical to go try it out). I figure I will get used to the Hcx "click stick" although the buttons on the 60CSx look more intuitive.
Although I don't have either (I committed myself to order one tonight and stop going back and forth) from what I have read we won't regret purchasing a high sensitivity unit ("H"Cx) versus one without.
As for the compass and altimeter, I myself am torn on the same thing. I will carry a magnetic compass, so why go through the hassle of calibrating the electronic one?
Anyways, this was more to bump your post because I want to see some feedback as well.
Sorry I don't have any real advice!