I used the joanns PUL and I did not like it, I found a better one on ebay, I also use the cozy flannel for the middle and a layer of pretty print cotton for the top..I have also use PUL diaper fabric but is more expensive.
here's the link to the PUL I use..
http://www.ebay.com/itm/Polyurethane-laminate-WATERPROOF-soft-durable-fabric-/130493169962?pt=US_Fabric&hash=item1e61ffc12a#ht_5 00wt_1029