We had Viva Window replace four windows and our back door. During the sales process they were very kind and professional. But the people who did the installation were in a rush to get in and get out as quick as possible. Their work was sloppy (they missed areas that should have been caulked). They also sent the wrong size window for one of the windows. They only realized that it was the wrong size after they had removed the original one, so they covered the area with a plastic sheet. We had to wait two weeks before they came back and installed the new window.
In addition to the poor service, I find that their product is of poor quality. It has been three years since we replaced our windows and door. There is a crack in the frame for one of the windows, we've contacted the sales rep to get this fixed but he never shows up. And the back door does not always lock properly, we have to really force the switch into place for the door to lock.
Their prices were comparatively lower than many other vendors, which is why we decided to go with them, but I guess at the end of the day you get what you paid for. If I had to choose again, I would not select Viva Windows, the slightly lower cost simply wasn't worth it.