Like any type of machine, you won't get the most out of your workout as if you were doing free weights, but it's still going to be better than nothing if that is what you have.

With free weights you tend to workout more muscles at once because you need to balance and stablize.

Here is a good article discussing the pros and cons of both:

http://ca.askmen.com/sports/bodybuilding_100/141_fitness_tip.html

You can build a pretty good home workout regimen without needing to get lots of equipment. For example, I have read of people who use bags filled with sand to do squats and deadlifts with

Those with yards may find a large, truck type tire and go beat it up with a sledgehammer.

In terms of 'other' exercises, you don't need a lot of fancy cardio. I live in a condo/apartment. No stairs, no yard, and in a ridiculously tropical climate. My cardio is 2-3 times a week of High Impact Interval Training (sprints) in my hallway. LOL. So I walk fast for 60 seconds, then sprint for 30 seconds. I do this for about 20 minutes. It works, it goes fast, and boom, I'm done.

You can get similar results with a jumprope (though, wow, that's intense) or sprinting outside.

Another possibility for you to consider is investing in 1-2 kettlebells. You'll want to definitely look into form & safety instructions, but a good fat burning cardio workout is 2 minutes of kettlebell swings, followed by 4 minutes of sprinting up and down a hill. Man, 2-3 rounds of this will kill most people.

HTH