Is Mountain Lion Support Essentials the same as Mountain Lion?

Do you "need to buy" Mountain Lion? No, you don't. Should you buy Mountain Lion? I certainly think so.

Here's one of the new features you'll get in Mountain Lion:

Mac Basics: Notification Center

There are other new items that I cannot remember ... Mountain Lion has been out for seven months.

Applications tend to be updated to take advantage of the latest OS X features. Why not stay current?

I'm guessing you mean the Books by those titles?

If so, I don't think there is that much different between Lion and Mountain Lion, except as sberman noted.

Some of the default behaviors for Versions and Resume have changed quite a bit, but you can probably sort that out quickly enough.

It's been a while since I ran Lion, so there might be a few more odd changes.

I don't know if it is coincidence or a defined pattern, but as with Snow Leopard being a refined version of Leopard, Mountain Lion is also appears to be a more refined version of Lion. There are a few more bells and whistles in Mountain Lion, mostly concerning iOS device integration. So, the old book is likely sufficient.

I can't remember if Snow Leopard had much more in the way of features over Leopard. Its big thing was the shift to almost full 64-bit, resulting in cleaning up the code base. It was the first OS X with the low price point. Many thought that was because it offered very little in terms of new features.