Everyone will have their own idea of "better" when it comes to the hard product. In the case of ORD-WAW that you mentioned, LO appears to offer more space per passenger. Case in point... LO 787-9 has 24 seats between the first two doors whereas United has either 30 (pmCO config) or 32 (new Polaris). On the other hand, all of the UA 787 seats in the new Polaris configuration have either aisle access or dual window/aisle access. For couples traveling, that might not matter or even be a negative. For single travelers, it might be a benefit unless you want an aisle-only seat in the center (in which case it probably doesn't matter).