I bought these as I thought I'd try something new and I must say that I'm not wholly impressed.
Despite my mixed review, I must say that they are indeed strong. The ones I've used have taken a good thrashing and still remained intact so that is my first plus point.
It's just the size more than anything that has lead me to not be so fond of these condoms; they generally tend to be long enough but perhaps not quite big enough for men with a thicker girth. Once I have had the guy I was with stop as he felt like the blood circulation was being cut off by the tightness of the condom at the base of his penis.
So while they're cheap and definitely strong enough, perhaps some consideration should be taken into buying them if you or your partner is of a thicker disposition