When come to 550 or 650 it really dosen't matter when come Hardware MPEG Encoder Video capture card there more then enough PCI bandwidth for up to 12 tuners or 6 DualTuner cards in a Media Server and some Client, but what would make a diff if this was going to be RAW AVI capture which need much greater bandwidth but the weack link we still have with AVI Capture are slow hard drive wite speed.
It really make no diff if go with PCI version or PCIe version but as fanbanlo point out if your planning to save this card for your Next computer which may only come with PCIe slot it maybe good idea to go with PCIe version in long run being the newer latest motherboard are start to drop more PCI slot and add more PCIe 1x slot which now 3 PCI + 3 PCIe as add-on card start come in PCIe version so it maybe 3 to 5 more years before we see only PCIe base motherboard but who know this is also change from year to year so i thard to say what can happing.
I was looking over the Theater 550 posts on newegg.com and found one saying you can't capture video when using S-Video as the input and that you can only view the video.
Not ture