I've also seen a lot of good reviews to the Sigma II Euro, but, unfortunately, nobody in my country(from what i've seen being a referee) plays this rubber. And that's a very frustrating thing, because i see every day someone posting how good is a Joola, Xiom, Stiga etc. rubber but i don't have the opportunity to try this rubber, because in Moldova, a lot of players use Acuda, Bluefire and Tenergy and only a few use other kind of rubbers, so I have two options : I either go for "verified" rubbers, or I have to risk and buy something according just to others' reviews or manufacturer description.
I would really like to know more about the rubbers you mention in your comments, se please describe them with more details, and I would be really grateful if you compare them to some Donic rubbers or Tenergies, like rajd1234 did.