OP here.
After days of some thought, I am leaning toward keeping FUSC.
Sure, monetary value alone, getting $5K back makes more sense. But...
1) Someone mentioned in another thread that FUSC fee can go up and highly unpredictable what the rate is.
2) Some people mention they would get EAP and I thought it was a good idea but this is something I can always add anything. However, once you drop out FUSC, you can't add it back most likely. Besides I didn't add EAP in the beginning because I wanted to drive this car. I have other Teslas if I need EAP.
3) I determined to do a lot of roadtrip in a few years. Who knows, frequent long distance travels can add up sizable $$ without FUSC.
4) I like the psychological effect of not worrying about charging and the cost. You charge whenever you need without worrying payment or late fee etc.
5) People think supercharging is waste of time, but normally I charge it on the way to work or home. Moreover, I spend the time working with my laptop while charging. Or take some rest and get power nap. Or sometimes take some lunch at the restaurant nearby the superchargers.
For those who have solar roofs and powerwalls and don't do road trip much, $5K is way to go. Like some people said, I know it will takes a few years to break it even, but I plan to keep my Model 3 more than 10+ years.
I will probably make more sound decision once Tesla make the final statement on this refund issue.