Lurker here. I've been reading this forum for a while, but I'm somewhat new to ballet, really avidly following it and attending performances for the last four years or so, so take my opinion for what it's worth --
I attended both the Friday and Saturday night Swan Lake, so I saw Copeland/Cornejo and Teuscher/Bell. I only went on Friday night to see Cornejo because I have never had the chance to see his Siegfried. Copeland danced both white swan and black swan. She did not do the fouettes in Act III and instead did the manege of steps. I don't like to be mean, but she was very mediocre. Her movements lacked musicality and her arms seemed clunky to me. She could not hold many of her poses very long. I was sitting in the loge, so if there was any subtlety to her performance, I didn't see it. Her Odile was bit better than her Odette. The crowd went wild for her, though, and it was cute to see a little girl there with her Misty doll. Cornejo of course was terrific as was everyone else in the company. Luis Ribagorda was a strong Benno. I find he has a striking stage presence with great characterization. The pas de trois with Ribagorda, Brandt, and Trenary was fantastic. And Jose Sebastian's Rothbart was sensuous and sinister (though he didn't really manage that balance).
Saturday night with Teuscher was night and day compared to Copeland. I saw her debut at the Kennedy Center a few years ago and she was even better this time out. I found her performance to be full of subtle movements and beautiful phrasing, She and Bell were great together. I really felt the romance unfolding between them. Thomas Forster danced Rothbart beautifully (and eked out more of a balance than Sebastian). The pas de trois with Royal, Stephanie Williams, and Katherine Williams (who subbed for Melanie Hamrick) was also good, though Stephanie Williams was weaker than the others. The cygnettes were almost perfect (with Brandt, Trenary, Erica Lall, and Anabel Katsnelson). Catherine Hurlin also really stood out as a big swan and one of the princesses.