The ATI card is bettern in both Digital and Analog. My Digital source is an Amplified Antenna to receive digital HDTV transmission. My analog source is cable.
The ATI tuner have 3D filters that improve the edges of the images. It works on both digital and analog.
The hauppage Analog reproduction is a degraded version. My friends who saw asked what have i done to my TV. I evaluated 2 1800 tuner from hauppage and end up with the same results.
One way to evaluate even before making the final-buy....
Get the tuner from local stores like Frys, Compusa, Microcenter, bestbuy... Check them out before the 14 day or 30 return policy. Thats what i did since Jan-08 i purchased and returned TV tuners from Fry's , and Best buy. It gives you a lot of flexibility to evaluate. Its perfectly legal and within the policy of the stores. Then you find what you want then buy it from newegg.
Spend sometime to try out the boards and find what will meet your requirements.
None of the existing Tuners i tried are perfect. You will see issues left and right. Its better to be able to try these tuners on your setup. It will help you make a better judgement.