Now THERE'S a question that's never been asked before! [8D]
Just kidding, Terry!
I think you've seen my thoughts on the subject, and they almost to a man match everyone else's on Bowtech's staff who's spent a lot of time behind each of the bows mentioned. MeanV2 and I talked a lot about this when we worked the Illinois Deer & Turkey Expo together, and we're also of the same mindset.
The Allegiance just simply does everything the Tribute does as well in terms of noise levels and shock, but offers if possibly a touch more stable platform and that added speed. Both MeanV and I had '06 Tribs and Allys to choose from all of last year every time we went hunting, and both of us ended up choosing the Ally every time. I think both of us ended up selling our Tribs at the end of the year. The '06 Ally is the only bow I kept last year out of thefive I had.
I should get my '07 Ally in next week, and I'm extremely anxious to put it through its paces and see how the weight reduction has affected noise levels and perceived vibration. That's one reason I kept my '06... in case it doesn't live up to my personal expectations of it. But I guess that's why I've got a Guardian hanging in my shop, in case noise and vibration becomes too big an issue...