Ya really cannot go wrong with any of the abovementioned bikes. All of them are good, solid (brilliant, really) performers.
After 30 some-odd years of riding I4's I experienced both a brilliant triple (Triumph) and a great Vtwin (Ducati). On my own personal bikes (I still traffic in any type of bike) I won't consider the I4s anymore. But then, I'm old,and you young folks are impressed by horsepower, and the 600 I4's make it in buckets. I like flexible and relaxed, and the I4's aren't.
I am sure that any of you young types could whup me arse on comparable bikes on the track. But I don't ride the track anymore. I ride the streets and highways where I seldom see the far side of the tach. I want bottom end and mid-range grunt.... all that top end rush gets for me is more points.
Don't get me wrong; push come to shove, if the only thing to ride is a Jap 4, by God I'll ride it. They are strong, fast and almost indestructable.
But just like the mid-eighties UJM's, they have become so alike that the differences are nearly meaningless. Some photoshop artist should take four side photos of this year's sportbike offerings from the big four and fill the fairings in in black and set them all side by side and you won't see a gnats difference among them. I was on a ride recently where we hopped from bike to bike (yes, it's considered bad form to drop someone else's bike) and I got to sample several of the latest and greatest from the big four, and to be honest with you, they pretty much all felt the same. Not one stood out. At least not to my old bones........
As someone else here said (quite insightfully, I might add) buy what gives you a stiffy. But just don't rule out the rest till you've had a chance to try them.
I once found a Triumph triple for a friend, and I had constantly made fun of his prediliction for things British,(kinda like Marko and his damn Buell) but after riding it to him a couple hundred miles over the back roads of West Virginny, I DID NOT want to give that bike up; and I SELDOM get emotional over most of the bikes I deal with.
My first exposure to Ducati was with a nearly giveaway ST2 Duc the owner got frustrated with because it ran poorly (water in the gas tank). My plan was to fix it and get rid of it, 'till I made the mistake of taking it on a blast up through the mountains, and I got hooked on the solid yet relaxed feel and absolutely left a group of riders on faster bikes in my dust. I kept that bike for three years and rode the wheels off of it, hard bags and all. Ya just never know what really will flip your trigger...........
Have fun in your search.