Betsson used to have a decent enough betting exchange however as they have changed direction in the online gaming space, they have closed the betting exchange. They now have a traditional online sportsbook product in addition to casino, poker and other games.
Whilst they are probably a decent enough sportsbook there are plenty of others that cater to the European market (and worldwide), such as Bet365. The Betsson affiliate program called Affiliate Lounge has employed some less than ethical methods with their partners and the end result being an agreement written in such a way that affiliate were unable to comply with the terms. When it was pointed out the affiliate manager refused to acknowledge the issue and merely ‘referred it to the legal people’. Two years later it was still outstanding. The arrogance of the affiliate manager made it clear they didn’t value long term partnerships.
So, whilst Betsson might be fine, do you really want to give your money to people that don’t care about their partners?