I bought these to go on my Epiphone Tony Iommi SG, tuned to D Standard/Drop C.
I had 10-52 ernie ball strings on it before this, but found that they were a little light and after putting these on, the guitar feels much better - the tuning is much more stable and the guitar feels more positive.
These are great strings for down tuning and feel the same as regular ernie ball strings, except that the coating makes them last 2-3 times longer. Very good value for money.