Not Much Difference Colossus 1 vs 2
Colossus 2 will accept and pass through 1080P/60 (the 60 is frames per second). However it records 1080P/60 as 1080P/30. Colossus 1 will only accept and record 1080i/60 (lower resolutions are the same for both cards). Whether 1080P/30 is better than 1080I is not really clear - a consensus view is that 1080i/60 is less choppy for fast moving scenes - although may be a bit blurrier. I upgraded to Colossus 2 because occasionally I get sources that are 1080P/60 and the Colossus 1 card just shows a black screen - no warning as to what's wrong. Then I have to go into a menu on the source and down sample to 1080i/60, which is a pain to do. So with the Colossus 2, at least I don't have to switch. Also, a minor difference, but the Colossus 1 shipped with ArcSoft Showbiz for capture. Colossus 2 has similar functionality with Hauppauge Capture, which by the way, can also be downloaded to work with Colossus 1.
Hope that helps.