If it's an upgrade to a nicer view, modestly larger room, or a Club floor, I am happy to take it. (I like Club lounges for the free breakfast, and for access to a space where I can sit and do work in the evening without feeling like a lonely prisoner in my room.) However, an upgrade to a big suite actually bugs me. To me a suite just means more places where I can potentially put down my stuff and then forget about it when I check out!