idrive is 2nd nature to me by now while on the move. As long as you know where the Menu button (by the thumb) is, you're golden. Think of it as a home key - then you get to whereever you want to go - I always swap between the nav and entertainment. I think it's very quick though initially it took some getting used to, especially the nav sub-menus... about an hour to figure the whole thing out but it's easy now.
If you can figure out navigating a cellphone, you can figure out idrive. A "back" button would've been great for this version though I'm sure.
And touchscreen is worse in my opinion - physically moving and watching what you're doing is actually a further step and does take more effort.
And comfort access is great. I've not once stuck the key fob in the slot... I'm not even sure it works.