These are fantastic strings! I have not found a single weakness since I switched to DR strings. They are extremely well made, last forever and seem to retain their tone throughout the life of the string (meaning that how they feel and how they sound match up, as opposed to a string that feels like it has not gone dead yet, but in fact has lost its tone) . I play the pure nickel strings, and they sound great through my setup, which is a P90 Les Paul and a various vintage tube amps. The sound is well rounded, with a lot of bottom end. They also feel great. They are soft and comfortable to bend, and do not seem to discolor or go dead the way that I remember nickel or nickel plated strings doing 25 years ago.
Overall these are a great value. I would estimate that they are lasting at least twice as long as the name-brand that I used to use, and I have now put them on all of my guitars. I recently purchased a set of the bronze DR acoustic strings, and those are great as well.