Are you talking about the difference between the main room and Queen Victoria Room or main room/QVR and Chef's Table? I've never done the Chef's table but we've done main room 6 times and QVR twice. I'll never go back to the main room (unless I can't get the QVR) if I can help it. It's changed a bit. I think you can now get the 10 course menu in the main room (I'm not sure if that's true or not) but you couldn't in prior years, but the QVR is always 10 courses. The attention is so much better in the QVR and the 10 course menu so much more amazing that it is now our preferred room.
Remy's is lovely but I would rank it slightly below V&A's only because they can't always get fresh ingredients. The service and attention to detail, the menu, the wine or champagne pairings are fabulous but because of the lack of ability to get fresh ingredients, it's not quite as good (we're talking marginal difference). But still great. We did the dinner, brunch, and dessert on our last trip and it was fantastic. We also did V&A's QVR the week afterwards and it was even better. It seems to get better every time we go.
DH did the 1-oz caviar upcharge at QVR the last trip (that's the 3rd time he's done that). I'm allergic to seafood but he thinks it's marvelous and looks forward to it every time. At Remy's he did the upcharge white truffle which came with every course and loved it so much he did the white truffle upcharge at V&As afterwards, although it's slightly different. Instead of coming with every course, you get it on a separate platter under glass and you decide what to put it on. He loved both.
V&A is pretty much the highlight of every trip to WDW. We usually sail on the Magic so no Remy for us; it's the only thing I wish the Magic had. But we did get to do it on the Dream and the Fantasy and we will definitely do it again on any of the ships where they have it. Fingers crossed they will put it on the new ships.
EDIT: While we love the QVR, the main room is also very lovely as is the 7 course menu. Harpist playing quietly during dinner (you can hear it slightly in the QVR). The tables are reasonably far apart so you feel quite private. Service is also really great.