Here are some pictures of the wax models Madame Tussauds made.
Now what I'm about to say is my own opinion and you don't have to agree with me.
From a distance, the wax models look a lot like the real ABBA members. The hair looks great and they look so lifelike. From an angle, Bjorn, Benny, and Frida look a lot like themselves. Something seems to be wrong with Agnetha's smile, her eyebrows, and her eyes. The eyeshadow looks a bit weird, too. From an angle, Agnetha looks a lot like herself from early 1975.
Frida has her nose and the same smile, just the mouth is too small. Like I said before, from an angle, she looks so much like herself. They got her eyebrows wrong, too. Also her eyeshape.
From the front, Benny doesn't really look like him. Something everyone should remember is that Benny's eyes are not blue, but a blueish-greenish color. (I do a lot of studying on ABBA pictures.)
Bjorn doesn't look much like himself either. His mouth is too big and they gave him a double chin. I thought Benny was the one with the double chin. Also, Bjorn's face looks too triangular. His shirt is a little too baggy.