The benefit of the CO seat is that it is much wider than BA CW, while still being as long and fully flat. It is a 2-2-2 setup on the 777, vs the 2-4-2 dorm on BA. While privacy is lower than the CW windows seats, the way the seats are angled (particularly the middle section on a 777) does make up for it. I personally find the CO BF seat to be much more comfortable than CW. Then again, BF is only installed on about 60% of CO's LH fleet (although that number is increasingly very quickly) while CW has been around for years in its current form. The UA seat is not as good as CO's, but I feel it is at least on par with CW in terms of comfort, and better in terms of amenities/connectivity/IFE.