We have the whole house 20K Generac. Yes it's noisy when going, but after we went through the Derecho Storm that hit this DC area a few years back and left us without electricity for a week, LOML said "Let's look real close at getting one". The once a week testing only goes on for a few minutes. When the whole neighborhood loses electricity, and all the generators kick in, especially the gas operated ones, yours won't sound so loud. Ask me we know as we had a couple going until they ran out of their own supply of gas and couldn't get gas at the local gas station during the Derecho. The gas station lost electricity too, and couldn't pump gas. Agree with the others that the whole house is worth the extra, for peace of mind. The exhaust we took care of by putting a stone garden there. In the stone garden we placed a small stone buddha in front of some decorative stone I got from a local stone and brick yard. It works reasonably well. Also, I thought that the Natural Gas Generac we got could be converted to Propane by just throwing a lever which changed the size of the burner flame. Similar to Outdoor Grills, they can be changed from NG to Propane with relative ease.
Additionally, I understand that Real Estate agents are looking at whole house generators much more positively than they did a few years ago. Certainly their presence continues to increase in our neighborhood.
Real American Heros don't wear Capes, they wear Dogtags.