Do you own the Maazel/CBS? I bought recently at donation store but have not listen to it yet. I own Karajan/Callas, and Leinsdorf/Price and one other I cannot remember. Any comments of anyone who knows this recording is welcome.
I do have the Scotto/Maazel/CBS. It is a good recording but it does not compare to others or even the Scotto/Barbirolli. I am not quite convinced with Maazel as a Puccini conductor as I think that he focuses too much on the details and lacks the forward movement the music needs. The second problem I have is the actual recording quality which has in my book too much reverb and thus occludes the music and the singers. Scotto's Butterfly is always special to me, vocal warts and all. It was recorded in 1977 so her vocal state is good still. I would place it after the Scotto/Barbirolli overall because of Barbirolli more affectionate conducting (and he sings too!

).
I find the Karajan/Callas the best of of the recordings I have of Butterfly. I will not repeat myself opinions by Steane, others and even myself in other threads that touched on this recordings. It is not just Callas at her most perceptive, communicative and tragic but also Karajan at his best. I find his contribution superior to the more famed Decca Butterfly with Freni and Pavarotti which is gorgeous but not as devastating as his EMI outing.
The Leinsdorf/Price is Madama Butterfly gone to Hollywood (no animus to offend anyone) IMO: gorgeous singing, a Technicolor recording (I have its SACD incarnation) but it is not a dramatic experience.
So, to rank the three recordings you list, I would say:
1. Karajan/Callas (topmost and by far),
2. Maazel/Scotto,
3. Leinsdorf/Price.
I hope this makes sense.
Cheers.