Which is better? Licensing your music/songs to a big record label (say Sony Music or Universal Music) or selling it digitally (Tunecore, Spotify, iTunes etc).

What is your goal?  What is your time frame?  What is your purpose? Without knowing that- I offer the following: The majors won't even LOOK at you unless you are selling a certain amount of units, getting so many hits on YouTube/Vimeo, etc. they want a KNOWN QUANTITY. They have the bucks to put behind artists- but nowadays that budget is very limited so they are very picky. But what they can do for you is help you be more far-reaching, and help you stay there with less of your efforts going toward the draining business side- freeing you to be more creative. So...  Start out doing your own thing. Do your own digital distribution, keeping track. When you sell 10K units AND have at least a million (combined) hits on media, hire an agent or music lawyer to contact them. As you can see... This will take time. So might as well have fun, right??  (-:

Licensing to a major label (if you're "lucky" enough to get such offer) will not give you any competitive advantage compared to handling this yourself with a digital distributor (like our company JTV Digital, or TuneCore, CDBaby...Etc.). Also catalog under license deal is usually not marketed at all within majors, it's just catalog building for them (following the logic "the bigger the better").

I think you're putting the cart before the horse. Who are you selling too? Do people know who you are? Why would anyone buy your music? What makes your music so special. These are the questions you need to figure out before going to digital music services. Ironically, these are the very same questions a record label requires answered before you even have a shot at being released by them. Start thinking about music like any other business. If you were selling burgers, first you would develop them, get them into people's hand to get feedback, find a way to market them, and follow a business plan for success.