Changing the color should be trivial, by looking at the CSS (assuming you know basic HTML or CSS).
When you say "populate" the sidebar, what do you mean? If you mean links and categories, you should do that through the admin interface, though I saw your other post that said the categories weren't showing up automatically.
Other things people add to the sidebars are plugins, and those are a bit more difficult, though you just need to copy and paste the code from whichever plugin's readme into your panel.template or whatever your template calls it.
From what I have seen comparing to other blog systems, is that LifeType lets you do more than any other blog system, but at the expense of being a bit more difficult to figure out, though probably the one that comes closest to LT in features is WP, and I think their templating system where you have to know PHP to edit the templates is more difficult than our "smarty" templates.
For myself, I don't see any reason to switch to any other blogging tool, and whenever people hire me to write plugins for other blogging systems, I always find that things take longer and are harder to be compatible across upgrades, etc. than if I can convince the customer to use LT instead.