Tough call for me. My favorite themes are movies, sci-fi, robots, spooky/horror...not necessarily music pins and kids shows.
I like GNR a lot, and I enjoyed the TS movies, however. There is already a GNR pin and a glut of music pins that have come out over the last few years...but TS is a bit "kiddie" for me.
I ultimately chose Toy Story because I think it had a lot more options/potential than GNR. If a reasonable amount of assets are acquired, its' possibilities are near endless (call outs, sound clips, video clips, toys/gimmicks, mods, artwork, etc).
P.S. I feel much the same way about LEGO (which I would love to see made into a pin, btw). It just has limitless potential.