I'd concur with Dan.
Both are fun, but both are different. More people at Red Wing (like 40+ more boats, and 100 more people), the river is interesting & fun for those of us who are lake boaters.
This year, Rathbun will get a few more 'Southerner's' as Old Red & Georgia and also Barb & Kat are making the trip, but not for Red Wing.
Its really a pick yer poison...though Red Wing is our Big meet...and if you can only make 1, I'd recommend Red Wing...its a blast.
If the river makes you nervous, then by all means, come to Rathbun!