In asking this question, you are looking for a way to know/decide which certification will bring you the most long term earning potential. In asking this, I'm assuming you mean "Which of these certificates will a potential employer look at and be more likely to hire me?"
If this assumption is correct, I think you're going to have a hard time finding a reliable answer; giving one would require experience with both organizations, experience hiring Scrum Masters, and knowledge of how these certifications are commonly viewed. Given that this combination is somewhat uncommon, you might be waiting a while for an answer.
Instead of Looking at the Value of the Certification
Lets look at the value provided by the organizations.
FULL DISCLOSURE: I have a CSM from Scrum Alliance but I'm not entirely familiar with Scrum.org (aside from the basic info floating on the net about how it came to be, and what is available on the surface of their site)
To get a CSM, SA requires a 2 day course and an exame I can say from experience the course was a 2 day 8 hours/day lecture type course and the test was pretty laughable (35 questions, multiple choice, iirc no time limit, and passing was 25 questions correct). In fact, some of the answers can be found by googling a few of the words in the question along with "scrum alliance". The cost I believe was around 1.5k for both exam and course (and the course is required) and comes with 2 years of SA membership. Some quick checking of available courses (https://www.scrumalliance.org/courses-events/course?type=Csm;) indicates to me that the Scrum Trainer you choose sets the price of the course.
Scrum.org's certification (PSM I) does not require a course, and each exam attempt costs $150. The test is 80 quesitons with a 60 minute time limit and a pass score of 85%. Questions are multiple choice, multiple answer, and T/F. There is also a PSM II exam which costs $500 and is a 2 hour long test. (https://www.scrum.org/Assessments/Professional-Scrum-Master-Assessments)
Once you have the certification, one of the biggest benefits to having these ceritifications is access to:
A quick check of both member directories shows:
Scrum Alliance with ~259,000 Certified Scrum Masters (https://www.scrumalliance.org/community/member-directory)
Scrum.org with ~32,500 Profession Scrum Master I's (in order to get II you must first pass I) (https://www.scrum.org/Assessments/Certification-Lists?AssessmentName=PSM%20I)
What This Seems to Come Down To
Scrum Alliance has more members, which means a greater chance that there will be other community members in your area; it also means there is a decent chance of finding a course in your area. Because SA requires an in person course along with the exame, and becuase the bulk of the community support seems to come from it's vast numbers and user groups, if you are the kind of person who likes to learn in person & with others, this is likely to be the best choice for you.
Scrum.org has fewer members, but allows you the OPTION of taking a course. Because the exam can be taken online, is less expensive, and does not require and in person course, it stands to reason that someone who is comfortable with a DIY approach may see more benefit from Scrum.org.
Why Have I Been Focusing On Learning When The Question Asks About Value?
Because you're getting the certification to prove that you have a certain designated process. However, if the knowledge required to get certifications was the only way of measuring aptitude as a Scrum Master, this job would be incredibly easy. Your value is going to come from learning after the fact, which can then be applied to your work, which translates into meaningful experience, and in turns bolsters your ability to speak to your abilities as a Scrum Master.