One can't help thinking that Rubini must have sounded a lot like Juan Diego Florez, for it is truly remarkable how well these arias with their many high D's and one E-flat sound in his voice. He is the Rubini for our time.
There is interesting information in Philip Gossett's note. Rubini continued the older tradition of light high notes and didn't follow the new fad for heavy, chesty high notes that became popular at that time. Instead, he sang higher than everyone else, and attained his greatest success in the repertoire of Bellini.
Question for C: Did Rubini and Malibran ever appear together? Gossett thinks not.