Both aircraft will be better than their predecessors
Better, but only just. The undeniable fact is that A320 is 20 years younger in its roots than B737. You can put new wing, engine, winglets, LED cabin lighting, etc., but it will still be good old B737 with almost zero respect for pilot comfort: manual switching (fuel, hyd, elec, pitot heat, you name it) pressurization panel design that might kill you one day, non-reduntant six-pack announciator that is a no-go item and doesn't give you ANY warning if the master caution button stucks in the pressed position, etc.
Sure, it's a nice aircraft to fly, but not for the ranges it's being able now thanks to the lower and lower fuel consumption. I don't envy guys flying BBJ, not even a bit.