In terms of speed, Windows will always have an advantage for GUI, since it writes directly to the hardware layer, and doesn't need to support other window managers, etc, like X-windows. X-windows has a disadvantage of being a client/server system, too.
But then, after adding anti-virus, etc, to Windows, it loses some of its advantages (but not all).
But I'm wondering about your issues with Ubuntu vs LMDE. Are you comparing apples to apples - ie, Compiz running on both with the same drivers and applications? I don't see why the "bloat", which is mostly just the size of the disk image, would make such a difference in speed. If you don't need some of the stuff running in Ubuntu, you can disable them. My problem with Debian was that it was always a hassle to get things I wanted to work. For a server or very basic work machine, it would be fine.
I used Ubuntu for years, and recently installed Mint because I don't like the Unity GUI. But I use Compiz for certain of its features, mostly multiple desktop support and ease of handling a lot of open windows (I do a lot of web programming, and often need to have editor windows, multiple browsers, bash windows, etc). Compiz makes it easier with things like showing all the virtual desktops in one screen.