There is a slight loss in "link juice" through a 301. So if Site A has the following pages (with all links pointing to it):
www.example1.com/
And Site B has these pages with links going to the following
www.example2.com/
www.example2.com/?linkid=101 (301ed to www.example2.com/)
www.example2.com/?linkid=102 (301ed to www.example2.com/)
www.example2.com/?linkid=103 (301ed to www.example2.com/)
Then Site A will rank slightly better than Site B all other things being equal.
You might also want to consider using the brand new Canonical Link Element on your pages instead of the 301. Here's a video from Matt Cutts of Google explaining why:
http://www.youtube.com/watch?v=Cm9onOGTgeM&feature=channel_page