Cool, will get the IS 4.
70-300 is not sharp enough at wider end and I don't need 300mm for anything.
OP already choose the 70-200 IS4, so we could actually close this topic.
...to be honest, there isn't any losers here, all three lenses are top tier and we really are splitting hairs between them. There has never been so much top end choice as we have available to us these days.
True, for me it boils down to this:
70-200 f/2.8 IS II: This lens's f/2.8 and prime lens image quality allows me to forego a bunch of primes in these focal lengths. It's also the best event/reportage lens. Comes at a price but is the absolute king and works fabulously with a 1.4 teleconverter..
70-300L: Get this one for versatility and compactness; the ideal travel tele-zoom with stunning image quality. The placement of the focus ring near the camera body makes this a little awkward to use if you like to (fine-tune) focus manually.
70-200 f/4 IS: The excellent 70-200 for people with smaller weight and /or budget tolerance. The only reason not to get this is if you already own one of the two other lenses (which is why I've not owned one of these personally).