The only thing that stands between you and appreciation of this RTS classic is a learning curve. Once you overcome it, you get immersed in an amazing sci-fi odyssey that dazzles the eyes and ears.
As far as the story is concerned, Homeworld has nothing on Starcraft, but its still a highly engaging storyline. The wonderful plot, which focuses far more on exploration and travel than it does on conquest, centers around a civilization in exile. Your ancestors were driven from their rightful home several millenia ago by a fascist empire and banished to a desert planet. Now, over the course of 16 missions, you have to lead your people across the universe to take back your homeworld. The plot is far from montonous, as the settings change and the mission objectives are wonderfully diverse. By about halfway into the game, you'll be hooked.
Homeworld is a 100% full-blown 3D RTS, meaning that you can move your units in absolutely any direction. As you can imagine, the interface is unconventional and thus complicated, but you can get into it easily enough. By the time Homeworld reaches its magnificent endgame, you'll be controlling your fleets in three dimensions with great ease.
The interface is impeccable. Logistically, it gives you complete control of the battle. Not once did I feel like everything was just too much to handle, despite the 3D-ness. Technically, its amazing. Homeworld is one of the few games that has honestly mesmerized me with its graphics. You can zoom in on any ship (friendly or enemy) and rotate the camera to any angle. Early in the game, you can be entertained just by watching your resource collector dock. If you zoom in, you notice the amazing amount of detail in each ship, and if you zoom all the way out, you can marvel at the beauty of Homeworld's balletic dogfights. You'll probably be doing plenty of both.
Bad things: the afore-mentioned learning curve, which is not as bad as it sounds (hooray for intuitive interfaces), and the early missions (the game doesn't really shine until you get the big units and the big battles).