I don't think Caldera broke away from Redhat. I DO know that Mandrake did, however. I also think that all of the major distributions make some sort of profit (or they would go belly up!)
1: Redhat (linux, currently at 7.1, prerelease of 7.2,using the 2.4 kernel)...this is the only commercial linux that's 'in the black' (meaning they make a profit). It's easy to configure both with text and gui installs and a complete newbie could install it easily. Recommended for beginners. Good RPM based system so installing patched programs from redhat.com is easy.
2: Caldera/Mandrake - these are versions that run under the same RPM system that Redhat had. Caldera used to be part of Redhat but they wanted to do their own thing so they split amicably. I wouldn't imagine there's much of a difference.