Its a really good question, and one which I find intriguing due to the recent onslaught of 4K@60p
Most of my cameras I've had, were limited to 25/30p in 1080 - so never really have actually shot much on my GH3 and GH4 at 1080p60 - i think the lure of UHD sort of spoiled the benefits of shooting 1080p60, and even now I'm hard pressed not to like my 30p stuff.
As the guys have said above, and from recent videos, underwater footage shot at 60p and played back at 30p - looks lovely. For me, its not that it looks 'slow mo' but that you get to appreciate the coral scenes more, the fish aren't so jumping around, the movement of the soft coral is more smooth and for sharks and the like, they look so much more defined slightly slowed down - yet you feel like the movement is still normal. On the other side, playing 60p back at 60p to me, looks awful from the youtube stuff I've watched - too real, too jerky and doesn't lead it self to storytelling - so for delivery to youtube etc I would still upload at 30p
I'm still shooting 30p at UHD, but instead of upgrading this summer, I'm going back down to 1080p and having a look at what my stuff looks like 2x slowed down.
As to WB - if I'm using lights, the WB is set to the Kelvin of the lights, or if not I'm Manual White Balance every few meters.