BOTH!
I like both - equally. I love to build - I started building 40 years ago when I tried to teach myself CL. I got the hang of it on about the fifth plane. Building today is much easier than it was back then. I also love to fly - so I gotta keep building. The problem is I tire of the old stuff so I am always building something new. Either way, it is a great hobby - building or flying.
Dan
PS: Yes you can fly at night. I have attended the KW meet in Kitchner Ontario the past 5 years and they always have a night flying demo. One more thing I want to build as soon as I can fit it in.