I figured I'd post this review detailing three Theatre 550 pro cards (ATi, Sapphire and Powercolor). The only difference between the cards are the remote and the brand of memory. The ATi uses 4.0ns Samsung, the Powercolor uses 4.0ns Hynix and the Sapphire uses 3.3ns Hynix brand memories. All three TV tuners come with the same software, Power Cinema 3. This without a doubt tells me that the ATi card is definitely not worth the price premium.
Review
About the only con to the cards are the included software. As mentioned by poster rbV5, Power Cinema is clumsy to use and does not include an EPG. Unless you have Win XP MCE you will need to use a 3rd party EPG. The recommended free EPG to use with this card is
GB-PVR. Beyond TV also supports this card but you have to pay a monthly subscription.
To summarize every review I've read on this product: This is the best TV Tuner, surpassing other cards well above its price point in terms of image quality. The black spot on the card is the included software being useless. Though, this can be fixed by installing third party software.
I hope this helps anyone looking to buy a TV Tuner.