Microsoft Windows RT - You can not run the standard win32 apps, like MS Word, Internet Explorer 10, Adobe Photoshop CS, Maya, 3Ds MAX, Picasa, Visual Studio, Rational Rose etc...
Microsoft Windows 8 - Windows 8 is a standard win32 (win32 is also supported on Windows-8 win64, this feature is called WoW64). That means, you can run all the above softwares in Windows-8 platforms.
That means, in your Windows-8 tablet, you can install visual studio, Adobe Photoshop CS etc.. but, you can not install these application in your Windows-RT Tablet.
However, windows RT supports Apps that are specially developed for windows mobile platforms. (Windows Application Store).
Which means, Windows-8 is definitely better than Windows-RT.