I hate those slidey power switches - they seem to be designed to break - and both my Kindle and my Kobo have them (and my two PSPs, but they're not relevant here
). It's always felt like the weakest link on the Kindle, occasionally sticking or not working, but the Kobo has been okay so far. It doesn't seem to need a lot of movement, and I can operate it even through the badly-placed elastic corner on my case. It is a year younger than the Kindle, though.