I kind of go in streaks where I do and do not use the Mac OS X Command Tab (⌘ ⇥) to scroll through my open applications. Of course, in keeping with the new flat, iOS look of in Yosemite, the icons are very flat looking. And, I think they are a bit larger.
If you have never used it before you hold down the Command Key (⌘) and Tab Key (⇥) and a list of your open applications pops up on the screen. You then Tab through the list to select which application to bring forward. Here is what the new Command Tab looks like in Yosemite: