Hahaha, like we're going to give you any answer other than the obvious?
Let's see:
1) Triumph is technically a better bike -- speed, handling, reliability, etc., are all superior with the Triumph.
2) The Triumph has all the history of HD. They were founded in the same year (1901 as I recall... And I think Triumph is actually a few months older).
3) The Triumphs are just cooler. Everybody and their mother have Harleys. They've been done to death. Ride a Triumph anywhere and you'll get looks, pointing, thumbs up, questions... And anybody with half a brain knows that Triumph is NOT trying to be a Harley -- back in teh day, Harley was more trying to be Triumph! (look at a sportster next to a Bonneville and note the similarities)
4) The Triumph is more cost effective. You get more bike for less money.
Did I miss anything?
--Jaeger