No I have never used them, but I do have a suggestion. If you are considering an off airport rental (which Payless is) try Enterprise. I plan on using them in Sept and got a rate of 13.95 per day on an Economy at the enterprise.com site. Just to clarify I have never used Enterprise either but have heard good things about them.
Payless is outside the north airport exit. For August and September (possibly October 2002 as well) you are better off going back through the airport and out the south exit to get to WDW, because of a huge detour where the Bee Line (Rte 528) connects to I-4 westbound. Returning to the airport you can come up I-4 to 528 to its Exit 9 Tradesport (cross under and then right at second light to Payless office) without any problem.