Fantastic durable strings
I am a lifelong user of Daddario strings and I always choose the EXL116 for my guitars that I use for playing in a full step down (D Standard) and drop C and these strings fit the bill every time!
These are some of the highest quality strings on the market for the price. I know some people prefer the more expensive brands but in my personal opinion (having used basically every string on the market) these strings have the same, if not better, durability and lasting life as the more expensive brands.
These strings give a perfect mellow sound for those bluesy/clean riffs but also have more than enough bite for rock and heavy metal. I highly recommend these strings for D Standard and drop C tunings! If you want to go to drop B or A, then I recommend the EXL117's which give you just a bit more tension on the low E and holds a great tone and bite, as do the EXL116's!