I've only played the tutorial and part of the first mission from Homeworld 1 so far so I don't have much to say about it other than it performs well. That might change when I get to the large scale battles, but there is plenty of options to tweak. I'm surprised I don't remember much about it apart from the basic premise. Other people have been saying they think the interface and controls are really clunky so it probably hasn't stood the test of time, but I haven't had any trouble with it (yet).
edit: I read on the Steam forums earlier that Homeworld 1 has the auto-balancing from Homeworld 2 and it's supposedly making some missions very difficult. Hope they tweak that.