I'm using Windows 8, and personally... I don't like any of the OS, but I would choose 8 without hesitation over 7. Its noticeably faster with my Intel SSD (330 series). The unity interface is a little annoying to me, but I do not miss the start menu at all... just find the unity menus a little unintuitive.
The Windows 7 start menu is gone, and replaced with the start screen (I don't know the technical terms). You can actually pin and un-pin programs from your start screen in Windows 8, and re-arrange theme.
The start menu "apps" are no good. The only "app" I use is the Weather one, and I actually really like it. The Hulu+ app would be nice, but most of the content I view cannot be viewed on devices and that includes the Hulu+ app itself even though its on the computer (yes, stupid). Thankfully you can unpin all the unwanted apps from the start screen, but they are still on the "all apps" page which I hardly ever view.
I personally would choose W8 over W7, but if W8 doesn't work well on a Mac (yet), then I could see the use for W7.