100gpd is actually a fairly fast/common output. The key is to have a storage facility for your water. If you are waiting until waterchange time before you begin to make water, I am sure it seems slow. I keep a 75 gallon tank filled with RODI for all my water changes/topoffs and the unit is rarely on.
I have seen water stored in many different containers. Depending on your needs, this could be a small or a large container. I've seen people use rubbermade trash cans. As for me, I happen to have a spare 75 gal tank in the back room I use. You shouldnt have to worry about the water going bad on ya.
Jeremy