given two people with similar work experience but differing by college degree, the preference will go to the master's degree over bachelor's degree, and either degree over no degree. That is true even when hiring at age 40 or 50 for senior-level workers and mid-level managers. [I was once involved with hiring my own boss, which is a very odd experience.] Positions highest up in the technical totem pole tend to go to those with master's degrees in addition to the decades of experience, and they are given preference over their peers with just a bachelor's degree.

I agree. For senior-level and such, the higher degree can be a decision maker. It might not be a benefit, though, to an entry-level person without much of a portfolio.

From happening to know salaries at one company I was at, I can tell you for a fact that they earn less than their with-degree counterparts.

Agree with this. Expect to be paid significantly more with a college degree. At most of the places I've worked at where I've seen the salaries of new hires doing exactly the same job the one with the college degree was paid more. I believe one study I saw a while back attributed this to the fact that most companies assumed you paid your dues completing college and most likely had a bit of college loans you needed to pay back.
So this is something for the OP to think about. If you never finish your degree even with raises maybe years later some new college kid will get hired and will be making more than you even though you have been working at the company longer. This is another reason companies don't like employees sharing salary information.
Other individuals might have very specific reasons for getting that piece of paper, like the Woz of Apple, he went back to get his degree in his 30's from what I understand. His main reason was to teach kids. In California anyways, they won't let you teach kids unless you have a Bachelors degree. Also, if you interested in working at NASA or any other government type jobs they won't even accept your application without a Bachelors degree, same goes if you want to be a military officer.
But like everyone said I wouldn't wait to long to complete it if you go the online route since you might end up taking 11+ years to finish like Scott Hanselman
or myself.