That drainpipe is one sweet lens.
I have had an 80-200 f/2.8 since before I went digital. I was looking for a bargain mid zoom and back then it was, I paid about $640 for it in excellent condition. First roll I ran through it, I was in love. I had been using a 28-105 3.5-4.5 USM II, after the first frames I saw from the drainpipe I knew I was in for a case of L fever.
In your comparison, I am a little disappointed in the Tamron's performance wide open. It's no comparison to the 80-200. The Tamron sharpens right up at f/4 though. I wonder how it stacks up against the Canon 28-70 f/2.8L.