Totally FWIW...
With today's software/drivers I've not been extremely impressed with ATI tuner performance... The picture looks good on 3 downstream TVs using the same feed, & QAM looks nice, but pure analog on the 650's is at best watchable -- right now [as usual] I've got the 2nd PC monitor off, & have the news on the 13" TV instead of the other way around. If I'm going to record anything other than QAM [which is just saving the stream], have to use SVID from the cable box if I want any quality at all. While there was slightly more overall noise, the analog picture itself was much better with the old ATI Media Center, whether I was using the 650 or the old AIW 9600. At that time, when I could use either MMC or CMC in XP Pro, the picture was almost as good using the 1st version of the Catalyst Media Center. In the years since, ATI has modded the TV chip drivers to turn on QAM, maintained compatibility with older, non-QAM chips, & made the drivers work with a variety of external hardware & the new AIW series. Together with Cyberlink they updated CMC [based on an older Cyberlink app] for Vista. A combination of both resulted in today's performance issues, e.g. GB-PVR shows a better analog picture than most anything else, but it's still not as watchable as old captures I made using MMC.
IMHO...
1) I'm not sure that today I'd spend more $ for more of a "premium" tuner card/dongle -- if I was looking at something around $100 or so for a name brand card [if the deals on ATI cards weren't available], I think I'd 1st at least try something like this $30 card instead.
http://www.meritline.com/mygica-x8550a-pcie-atsc-qam-fm-tuner---p-36181.aspx
2) I picked up my 1st AIW because there wasn't a comparable 2 card solution. I picked up the 2nd because 2 cards then would have cost (a fair amount) more. Since then HD's happened, nvidia & ATI have added hardware video acel to make watching it easier, & CPUs have gotten more powerful, to help make HD only a bit more troublesome than SD used to be. Vista & 7's Media Centers work well with multiple tuner cards/devices. There's a huge difference between the 2XXX series & 4XXX series ATI cards I picked up only a year apart. I wouldn't give up that flexibility, &/or deal with any potential reduced performance [the added circuitry takes the place of features on a regular card] from an AIW again.
3) For quite a while there were problems with ATI's theater chip drivers, & some of my problems stemmed from their added-on compatibility with ATI USB tuners... rather than write USB drivers, they *adapted* them with a commercially available software add-on, that's included yet today. While the problems it caused me have gone away, I frankly would be suspicious of any ATI USB hardware using that add-on [it's a coding time-saver, adapting existing drivers to use USB via a hack that has definite consequences to Windows].
4) Hardware encoding is probably a good idea for H264/AVC, but as ATI advertised themselves back in the days of the AIW Radeon, irrelevant for mpg2. [That was how they sold the card -- up till then CPUs weren't fast enough & you needed hardware encoding]. Of course the adverts changed with the theater chips, but they also had hardware mpg2, so all of a sudden you needed it again. Funny thing though -- the AIW 9600 encoded mpg2 with a 20 something max bit rate [comparable quality to DV], while the theater chips could/can only manage 12. AND, when I was running the AIW 9600 & 650 theater both, CPU usage during mpg2 capture was less on the AIW!
That all said, now thru summer is when prices traditionally drop, & old stock, including ATI is cleared out etc. CPU prices are going to drop, so unless you have a compelling reason, if you want to buy, buy in a month or two -- last year I really needed to replace a rig, & not waiting 2 months cost me ~$40 [waiting 8 months would have saved me double that]. If you're buying a m/board, don't go economy class -- you don't have to buy the best, but the cheapest enthusiast models are barely more cash, & a world of difference, e.g. bios settings haven't been removed to justify economy pricing. Balancing that I've read chip manufacturers shut down plants rather than suffer a glut of product during this recession -- prices are supposed to rise substantially... All I know is RAM prices are 2X last year's.
What that means is that to *Some* degree you can mix & match the versions of t200 device drivers, Avivo files, & the graphics card drivers proper, & that [in my experience anyway] the TV end of things can vary from 1 month's version to the next. When I was still running the AIW 9600, & now with the 650, I check video-related performance after each monthly update, & go back to what I was previously using as needed with any of the 3 -- usually just the wdm or Avivo though. I also edit the Avivo settings in the registry after every driver install -- making controls available in CCC, & being able to change those settings has proven critical many times so far, as different driver versions have broken different aspects of video handling & different apps, & those settings can help in often unexpected ways. Note that it doesn't hurt to do a backup 1st, as it can sometimes be near impossible to go back to an earlier graphics card driver version.