Though it would require using UA up to ORD (or EWR), I would also consider SK, they seem to be getting good reviews on the new biz seats. They have a direct ARN route from both ORD and EWR. As far as UA goes, their new seats are good as well, but you'll loose a bit in service with some crews. You'd need to go to LHR or FRA, etc. and change to an SK or LH flight from there.