I am making a site that compares products - might make it so users can submit reviews. Whats better: youcompare.net youcompare.us (You Compare Us) decidebetween.us (Decide between us) The third option I could even make subdomains with, something like: IEorFirefox.decidebetween.us Which do you prefer?
Compare.Us must be taken. Either find a good synonym and play on the word "Us" or think outside the box and get a good .COM.
Be creative and try to find a good .com domain that is available. It's better to have a long domain name with .com than the play of words with anything else. Just my $0.02.
what kind of products will be compared? You might want to incorporate the type of products into the name. In my opinion the three choices you have listed are too general. Just a thought.