It looks like some people only used Amigas because they liked the ugly look of the default Workbench.
You all know the reason Workbench looked so plain to begin with was to inspire you to create something more visually appealing with it yourself? It's a blank canvas for the creative mind. It has always been more configurable than other systems, especially MUI which lets you determine the frame, fill, font, background textures/gradients and pixel distances for every single component of the GUI on a per-program or global basis. You can make one program look like Workbench 1.3 and another look like Windows Vista, it's all up to you, and it always has been with Amiga OS and MUI.
If you're not interested in operating systems at all, and consider a computer nothing more than a tool to get work done then you probably won't get anything out of MorphOS that you can't do on a generic PC. But if you're an Amiga enthusiast you owe it to yourself to give it a go and see how good an Amiga OS can be.
Now to explain a little about the configurability of MorphOS, I have taken a few screenshots showing different MUI settings. I didn't change the window frames, but those can be changed as well of course.
The screenshot I showed earlier was how I prefer to have it look, I configured it that way myself. This is the default MorphOS look:
http://i54.tinypic.com/2h50581.pngThis is one of the default themes to choose from, for those nostalgic for the past:
http://i54.tinypic.com/200wyea.pngAnd here it is the way I have configured it to look for myself:
http://i52.tinypic.com/2m85o1x.pngBy the way, changing the look of MUI in MorphOS happens in real time. All the programs you are configuring will change their look as you adjust it without having to Test it out first, you can see how it looks as you fine-tune it to your tastes.