If you are interested in viewing the latter in person, the best place to go is Vienna, and once there, I strongly suggest visiting the Belvedere, which has his iconic "Kiss" (1907-08). More information regarding Klimt is here.
For what little it might be worth, I'm not enthusiastic about most of the people-related paintings he made during the last six or eight years of his life.
No decorative detailing here. Perhaps Klimt was in the process of reconsidering his style.
Although painted several years apart, Klimt used a similar composition for these portraits -- the subject facing the viewer, taking up roughly the middle third of the painting with the rest occupied by decorative elements to varying degree.
For much of his career, Klimt painted "busy," detail-filled paintings. Here the contrast in colors between the subject's flesh and most of the rest helps pull the lady's image into dominance.