I am viewing the finished video on the same computer screen as my sequence, and side-by-side, they are noticeably very different.
That's not quite good enough. You really do need to get the image onto a properly calibrated TV, taking all software and graphics drivers out of the equation. One you have that in place, you will have some reasonable assurance that you are seeing the signal correctly. Until that's done, you can't have any such assurance as the operating system, graphics driver and even software player can and often do alter the signal.
So...get those exports onto a calibrated TV, and then judge it's quality. And for any meaningful comparison, you'll also need to get the originals onto that TV.
