Let me get to the punch line first. This is almost a "must buy" despite my 4-star rating which I'll explain below.
In the last several years, it's extremely difficult to keep up with the young ballerinas coming up the ranks. The Russian schools seem to have put out an unending stream of really talented and accomplished young female dancers whose names would require memory training to retain. Polina Semionova, Alina Somova, Maria Alexandrova, Alina Cojocaru, and one Osipova. Any more?
They are already principal dancers in the major houses - Bolshoi, Royal Ballet, Kirov, Berlin - and they all have "stories" attached to them if you read about them on Google. Semionova was specifically recruited by Berlin to partner Malakhov; Plisetskaya was so impressed by Somova that she took off her diamond ear rings and gave them to the awed young woman; Cojocaru turned down an offer of principal dancer by the Kiev Ballet and joined the Corps de Ballet at the Royal Ballet so she could improve more freely. I believe it. This is exciting stuff.
This Giselle was danced by Alina Cojocaru, a Romanian trained by the Kiev. She's fabulous. Every movement, turn, jump, and pose was precise and beautiful to look at. She also paid great attention to the story and acted very well. The ending of Act I might even be a bit over dramatic, but she was committed so I would not fault her. In Act II, the Corps was on stage 80% or more of the time and the ladies were magnificent. You wonder whether they tried extra hard to support their former colleague from their rank. It's one thing to do grand jete in ones, twos or even fours. But these women gave me the impression that they were FLYING in precision formation in the same split second as a squadron. I watched the second act three times in a row.
So why only 4 stars? Ah, great ballet has long reaches and memories. The one big shadow for me is the 1977 American Ballet Theatre Giselle with Markarova, Baryshnikov, and Martine van Hamel. Others may have theirs because there had been so many great Giselles over the years. Galina Ulanova, Alexandra Ferri, Carla Fracci just to recall a few. Don't forget several other Russian ladies whose names I can't spell anymore. Many of their performances had been preserved on film. Man, it's a tough crowd!
One also has to think about the Albrechts and Myrthas (we can forget the Hilarions for simplication of comparison.) In this Giselle, Marianela Nunez was wonderful, practically in the prima ballerina class in which I think she actually belongs. But Martine van Hamel was perfection, so good you could cry while watching her. How about Albrecht? Kobborg was good. However, he's no Erik Bruhn even though he's Danish. Baryshnikov was already a trademark in the late 70's for reasons other than looks and hype. He's one great dancer! It's almost not fair to compare.
Finally, there's the conducting. The Russian maestro Boris Gruzin must be a very considerate man. He gave the dancers all the slack they needed. As a result, his beat tended to follow especially the soloists, not lead them or urge them on. This had consequences. The music lost propulsivesness in several key scenes, especially when approaching crescendos and climaxes. The virtue on the other hand was that the dancers looked good on stage because they "finished" at the same time with the music. But I prefer the tension of the music over a perfect pose.
John Lanchbery conducting the Markarova version was never pushy. He just kept a tighter rein. In fact, his tempo in places were slower than Gruzin's. Markarova must have loved him because he let her move and let the music "surround" her movements, neither leading nor following. It took me many hours listening to Lanchbery's Swan Lake to realize what a great ballet conductor he was. He did not conduct as a symphony conductor, but as a ballet master.
So why is this Giselle a Best Buy? It's a modern rcording. HD quality and surround sound. Young Cojacaru was simply a delight! Technique, acting, and total dedication to the role. The Corps to me was women's beauty at its finest. Then look at the price. Unbeatable.