I have been using Whisper air pumps for as long as they have been on the market and never had any serious issues with them at all. I found an old large dial model at a garage sale once for $1.00 and 12 years later, it still worked with only one replacement kit needed.
Here is a link to Foster & Smith website were I buy my supplies.
http://www.fosterandsmithaquatics.co...8&pcatid=12738