Although not specifically listing SDM lenses the LensPlay Lense Failure Survey has some interesting results :

There have been responses about Canon lenses from 2960 users

There have been responses about Sigma lenses from 1509 users

There have been responses about Tamron lenses from 949 users

There have been responses about Tokina lenses from 363 users

There have been responses about Nikon lenses from 558 users

There have been responses about Pentax lenses from 350 users

There have been responses about Minolta/Konica/Sony lenses from 182 users

There have been responses about Other lenses from 351 users

Lens Defect Survey
Survey Results

Note: Values are greyed out if there are less than 300 lenses sampled

Canon lenses - 13134 with 1001 defects

The probability of getting a good lens is 92 %

The probability of getting 5 Canon lenses in a row is 67 %

Sigma lenses - 2974 with 668 defects

The probability of getting a good lens is 78 %

The probability of getting 5 good Sigma lenses in a row is 28 %

Tamron lenses - 1476 with 217 defects

The probability of getting a good lens is 85 %

The probability of getting 5 good Tamron lenses in a row is 45 %

Tokina lenses - 496 with 81 defects

The probability of getting a good lens is 84 %

The probability of getting 5 good Tokina lenses in a row is 41 %

Nikon lenses - 2417 with 199 defects

The probability of getting a good lens is 92 %

The probability of getting 5 good Nikon lenses in a row is 65 %

Pentax lenses - 1539 with 99 defects

The probability of getting a good lens is 94 %

The probability of getting 5 good Pentax lenses in a row is 72 %

Minolta/Konica/Sony lenses - 654 with 61 defects

The probability of getting a good lens is 91 %

The probability of getting 5 good Minolta/Sony lenses in a row is 61 %

Other lenses - 959 with 97 defects

The probability of getting a good lens is 90 %

The probability of getting 5 good Other lenses in a row is 59 %