I'm going to be lynched.
I've never ridden a track frame, nor do I really care to. I'm a roadie at heart. I love road bikes, I love road geometry, I love lycra and coolmax.
For me, a converted road bike just makes sense.
I can set up similar positions between my geared and fixed, so transitioning between the two is never a problem.
My fixed sees more commuting miles than anything, so the semi-horizontal dropouts let me run full fenders and still get the rear wheel out.
And for hilly century riding, a friendly/forgiving road frame is just right.
Track bikes look nice. But for me, that's about the extent of their appeal.