Just last month I had to fix my neighbor's wifi. We had to update the router firmware and find a clear RF channel. Some owners can't do this so yes, for them it will be unreliable.
My isp said that using a router is unreliable, and for $5 a month i can pay for their wireless service. Surely people are doing this successfully, but I just don't know how. What would they do differently that what I can do with a router with the right range?