I've been to AmiWest once back in 2003. That show was a coming out party for Genesi and quite a bit was going on. That said, it still was nowhere near what Macworld is. From what I hear, AmiWest is now much, much smaller than it was in 2003. That is not to say you won't enjoy yourself, just don't expect a really big function. Think small.
Judging by the list of attendees, demos, and seminars plus additional coverage of MorphOS, Classic, Classic repair, the Friedens coming from Europe, Carl Sassenrath, Jamie, etc. etc. and the new record # of banquet tickets sold, I doubt this will be small.
However, I don't have the 2003 # you refer to, so I can't offer you that comparison.
#6