Mine loads a bit slower, never really timed it but I know it has never loaded in 3 seconds, lol. Do you find it really different then windows or is the setup still pretty much the same. I mean like the taskbar and start menu and such. 
Well, it is pretty different from Windows.
Active applications are marked in your Dock with a little white dot beneath it.
The top bar is mainly used for status controls and the File, Edit, etc. menu.
The start menu...Macs don't have one

But we have Launchpad. It's like an iOS home screen.
Something I find great about Macs is Mission Control. It's like ALT+TAB on Windows but in this way you get a complete view of everything going on, including full screen applications.
The full-screen feature is also great. Now you don't have to un-full screen an application to get to your desktop but you can just swipe with 2 fingers over your Magic Mouse or Magic Trackpad and you are back to your other apps.
The Magic Mouse you get with an iMac is a great mouse, but the secondary button is a bit getting used to it. You don't feel like if you are on the secondary button or not, it's just like a touchscreen.