I used this set on my Ibanez RGR321EX, took them on and off when I changed the pickups, then the same thing on my new Epiphone SG. These strings are indeed tough. They remain clean, without getting rust. My impression is that they are elastic though they keep their tuning quite well.
Sound-wise, they are what they are claimed to be: transparent sound without that "nickel" character. They are easy to handle, neither too soft or too hard. Seems like these are the best strings I have used, so far - they do their job and I am focusing on something else.
As a side note, a good thing about the Ernie Ball strings is that they describe the tone and sound differences between their strings on their website, it is easy to find what you look for. I also bought an acoustic string set for a friend, and I really got it right just by knowing what his guitar sounds like and needs to compensate, then compared the products at Ernie Ball.
My next set will likely be the same, unless I will want to experiment different string sounds.
Pros: neutral sound, warmer and not that resonant compared to the average strings. My sound varies quite much and these strings are versatile enough to accommodate needs that not often found at the same guitarist. The sound character can be tweaked from effects (mostly EQ-related), when you build your sound from scratch, and these strings don't generate quirky harmonics that need to be suppressed.
Cons: not necessarily a drawback, but you might reconsider if you need classic bright, saturated lead sustain or something. This largely depends on your setup - guitar, pickups, drives.
