All
When I demonstrate cooking on the Kettle, I always use the Slide Aside, It may just be my salesmanship but it convinces many users to go and purchase one because of the sheer convenience. However, many very long time users prefer the lid hook, because they are so used to using it, that it is second nature. My two bobs worth (IMHO to use a more recent term) is if you have trouble storing the lid when removing it get the Slide Aside, if you are using the hook then continue.
I always use the hook at home.
To overcome the problem of closing the vent and more importantly to ensure even heat distribution, I always encourage users to orientate the vent so that it is in the centre of the kettle facing forward, the slide aside should be positioned at the rear.
I know, the kettle is round so how can you have a forward position - I call the leg without wheels as the forward leg and orientate everthing relative to it. It makes it so simple then to explain and demonstrate.
Regards