Anyone used Zalyn for car rental discounts?

[cz4ever]

I track a number of frequent flier blogs over on BoardingArea, and one of them recently highlighted Zalyn, a website that tracks rental car coupons and discount codes and lets you search for what codes/coupons are best for when/where you want to travel. I've poked around and it looks pretty dang good, including identifying stacking coupons that let you pile up the discounts. Does anybody here have good/bad experience with them?

I have access to extremely deep rental car discounts through my (huge, multinational) employer, but some of the codes from Zalyn even stack with the corporate code. Niiice.

Barring negative feedback, it seems like a site that folks here could really benefit from...

Apologies for the lack of link, but my post count is too low to be allowed to include images or links...