I recently flew BF ICN-SFO and then IAD-GRU later that day. While it was nice to not be sitting in Y I have to say the FAs make a big difference. The FAs on the first flight were outstanding and some of the best I've seen in a long time. The FAs on the GRU flight were ok. Because of a late inbound I was one of the last people to board the flight and I was afraid they were never going to take my dinner order. I was also afraid I had missed breakfast while I was sleeping it turns out they just did it ~45 minutes before landing.
On a side note a bunch of my colleagues that I was traveling with got Op-Uped on the ICN-SFO flight. None of them had ever traveled in anything other than Y or sometimes E+ and many of them said it was the best flight of their lives.