Now that's a an interesting question, but a reasonable one. If you're happy with the Mega you have to ask if you really need the S-Pen functionality, the IR blaster, and the S Health features. I've gotten so used to taking the 2GB of RAM for granted that I had a lot of concern about the Mega's 1.5GB and if that'd be enough. Yet, 2 years ago 1GB was the norm and phones were fine with it. I'd say unless you have a problem that the Mega is not solving it may be easier to stick with it. Or, you could indeed sell it. The Note 3 is quite a phone too and the screen is really really nice.