The trend I am seeing here is that a lot of people emphasize on the importance of E+ or SWU and are willing to forgive UA on everything else (even *A blocking? what's wrong with you guys

).
While E+ is nice, it's not going to make a "huge" difference unless you are tall and unless you can snatch that row 17 on a 777. With 747? Forget about it. I think someone on FT once told me that "there's ZERO good E+ seat on a UA 744." Before becoming a United 1K, I have flown tons of TPAC on JL, CI, and NH (all in Y), and have never complained about their Y seats being too small (and I am 6ft tall).
As for SWU, it's nice to be able to upgrade once a while. But, if you read many of the recent FT posts, you will know that it has become more and more difficult to clear those SWU. Do a search and you will find many 1K, GS, MM lamenting their first experience of not having SWU cleared.
Unless you fly for leisure and have a great deal of flexibility in your schedule for you to find that elusive NC space, it's difficult to use SWU because SWU upgrade is no longer a sure thing even for top-tier elites. Not only do you have to fork out extra money to book in W, all you get is a chance to upgrade, not confirmed upgrade. As a business traveler, I just don't have the luxury to be flexible and find a day with NC space.
So E+ and SWU are just not THAT attractive. If CO offers a better experience (and it seems like they DO from pigx5's pictures) and competitive fare, then I will not hesitate to fly with them in the future.