I bought some of these as I'd heard great things about Infelds; tone and string life were the main things. I'd suggest that perhaps the very expensive Infelds could live up to this billing but these ones are very much the same as it's similarly priced competitors; Ernie and D'add. Used D'adds for years and honestly didn't notice any difference plus string life wise I had a breakage pretty much when I always do ;) Pretty good but nothing special.
A little more expensive than a lot of better known brands, but I went for these as I always liked their flatwounds. These are among the best guitar strings I've used in my 30 or so years of playing. Bright, clear and have a lot of power. Great sustain on both my tele and les paul and fast action. Great when piledriving effects!