Quite frankly, I believe these are very good strings. Out of the box, they might be a little less bright than their £ 25+ counterparts, but they definitely fit the bill. No difference would be heard in a live setting, mind you, and there is really no reason to get more expensive strings unless you have quite a unique feeling with them. I've had them on for about a month, so I can't really speak about how long they last. They're still quite bright, though. I might use the thomann vouchers I have to buy some extra packages, so I don't have even risk remaining without.
These strings feel very nice. In terms of tension, I would say that they are not as stiff as D'Addarios or Ernie Balls. I like that, but you might want something different if you are a heavy picker or whatever. They are not as coarse and rough as Warwick Red Label strings (thank god).
I currently have these strings on a P Bass and they sound quite right. I can see myself putting these strings on high-end instruments without hesitation.
Give them a try ? you have very little to lose, and you might like them. :)