I haven't been to all the vegetarian restaurants in Colombia, but I've been to many. This one is definitely one of the best. You never get boring food here... they really take time to think up things that make the food great. In addition to the great flavors, the meal is always balanced and provides protein in some form. The girl who works there told me they only use milk & egg products when the customer asks for something special; the meals of the day are apparently vegan.
They have 2 different meals of the day. There's the regular meal for 6500 pesos (as of December 2012), and the special meal for 8000 pesos. The special meal has a little more food, and is a little more elaborate. You can count on either one to be really good. I don't give five stars (or in this case 5 cows!) very often, but this place deserves it for the great food and the very reasonable prices.
To get here, you can take a taxi, or take public transit (take the Mio bus system to station Vipasa; walk west until you get to the train tracks. Don't cross the tracks, instead turn left and follow the road along the tracks and the restaurant is on the left in just a few blocks). This is a very safe neighborhood to walk in.