@loke
I have no idea why people love Galaxy and hate Sunshine, or vice versa, outside of personal preference.
I personally wasn't a fan of Galaxy. When it first came out I thought it was fun and it looked good, and the gravity mechanic was cute, but the soundtrack was too... "big" for me. I didn't care much for starbits, either.
First of all, Sunshine felt more like a world. If you look out into the ocean in Sunshine, you can see the Ferris wheel from another level. You got a sense of location, like "I'm here,and that's there". I didn't feel that in Galaxy.
I also like the overworld in Sunshine. There are lots of secrets and easter eggs, and since there's no real chance of dying it gives you a lot of opportunities to master the different methods of getting around.
I won't go on about it anymore. I just think it's a really charming, somewhat whimsical game and I appreciate it.