I have been using these strings both at home and at gigs. I mainly play rock and these M-steele are really good for that purpose with it's higher output. They are really crisp and clear.
They feel a bit different than your standard Ernie's. They feel more rigid of some sort, a little bit in direction of feeling coated, however they are NOT coated. And they feel only slightly different than your average Ernie's, but it's not completely a game changer because it's very little, some don't even notice.
Higher output, smooth feel, and they last longer than the standard. I've been rehersing serveral times and still I used them at a gig without hesitating because they are still ready to rock.
I would say that it's reasonable to buy these M-steels, the price is bigger, but they give you that extra in your tone you maybe have been looking for.