The experience on BA and VS will differ significantly depending on the specific aircraft flown.

On BA, if it's the 772, 77W, 351, or 787-10, that will be their club suite, which is very nice; if it's the 380 or 789, that will be their old club world seat, which is to be avoided.

On VS, if it's the 351, that will be their new state of the art suite; if it's the 789, that will be the old herringbone seat, which is to be avoided.

Unfortunately, both BA and VS are prone to aircraft swaps, so regardless what aircraft is currently shown, there's no guarantee which seat you'll get. On UA, you'll get the Polaris seat, which is decent, regardless of the aircraft type operating the flight.

On soft product, BA is similar to UA in that the service and food are inconsistent, though overall I slightly prefer BA over UA. VS is better, but there's still that uncertainty over the seat.