Martin Logans

I have recently listened to the ML Theos and was very impressed. I was curious if anyone has listened to the Ethos vs the Vantage? I would really like to have a powered woofer that either the Ethos or Vantage provide over the Theos. I have not been able to listen to the Ethos but they are much more expensive on the used market than the Vantages (4,500 vs 2,500) Anyone know how significant of an upgrade this would be?