I cant praise them enuff m8. I have been using ventura on all my bikes since 2005 for big euro tours.I love how they dont block the airflow and are so quickly detachable. I usually bungee a grip bag to my pillion seat and have the ventura bag on the rack. This year I picked up a 15 litre second bag which zips to the main 51 litre bag, so this will save all the bungeeing.I can carry everything I need for a 12 day trip in the bags, with usually spare space. I also have a baglux tank bag for all my bits and pieces and documents etc.
the big bonus of ventura is if you change the bike, usually its just a case of buying the new side rails, as most pack racks are universal. There is a lot of ventura stuff on ebay, and it usually fetches good prices- always an indicator of how popular stuff is.
I leave my side rails on all year and bought the grab rail to fit on when I dont use the pack rack.