Yes you will have access to the AV lounge, although I agree that the only advantage over the CM lounge are the windows.
If you have an AMEX Platinum card, you can go to the AMEX lounge, which is a smaller version of the Avianca one, with the same food, but unlimited drinks (including beer, wine, spirits, etc.). In the AV and CM lounges you are given one ticket upon entry, which allows you to claim one complimentary drink at the bar. That's all you get!