So Pixar exclusively does CGI, right? And yet Bolt is the best use of CGI in a recent motion picture, which happens to be from Disney.
You say this like it's a given. Like it's a fact. And I feel most (if not all) of us completely disagree with you. I wish you would at least make some attempt to explain how Bolt uses CGI better than Finding Nemo, Monsters Inc., Wall-E, Toy Story, Toy Story 2 etc.
To my ears you might as well be saying that actors give their best performance when Michael Bay is behind the camera. That's how much sense it makes.
Individually, Wall-E has the best single use of CGI I have ever seen, that comes in the form of the Space Dance sequence, but the amount of detail packed into Bolt is truly astounding, the only other film that comes close that I have seen is Finding Nemo, which is what I shall be using as a comparison for the majority of my reply. First, we start with people, Pixar's most glaring flaw in every film aside from the Toy Stories and Nemo. Now both films show they are capable of rendering humans realistically, but the amount of screen time they are given in Nemo, where I would say they are at their best, is so minimal that it may just be that they serve as another piece rather than a Testament to Pixar's ability to accurately portray humans while still keeping to the semi-fantastical realm. Conversely, Bolt gives its people some cartoon-ish qualities, but the level of detail packed into their faces and the variety of people on screen during the film to show that this is no coincidence, serves as a fairly accurate account to the studio's ability to handle humans in larger roles than Pixar, for example The Incredibles where absolutely no person looks remotely believable or incredibly detailed. Disney gets the decisive edge in that category.
I have two more points that I would like to hit on, animals and environment. Monster's, Inc is good at showing off both animal-esque animations and detail, as Sully's fur is incredibly detailed and even Randall looks great despite just being scales, but then characters like Mike's love interest just seem half assed. So I'll look at other Pixar films. First we'll throw out Cars, because I haven't seen it and because you can't animate a car realistically or believably when its jumping around and talking. Next we'll look at Toy Story, I have few complaints, all the characters are incredibly detailed for the time and behave realistically and imaginatively, but because of the gap in time the CGI in Bolt is noticeably more refined. Next we'll look at Wall-E, I can agree that Wall-E behaves realistically and imaginatively, but the detail does not really scream out as impressive for me, on any of the characters. This is largely because animating robots should not be incredibly difficult, they only have a fixed movement pattern with little room for deviation, so once it's gotten down then nothing else should be too hard. Finally I'll move to Nemo where the fish are beautifully coloured, swim incredibly realistically but are not questioned when they do something fantastic because the world between the real and the cartoon is so well blended. However, the problem I have here, as expected, is that everything is too one note. That encounter with the fish that has the light on its head showed an incredible skill with CGI, but color is nice, however fist really only allow for different shades and different constructions, there aren't really fine details that need to be ironed out. Conversely the animals in Bolt are all incredibly detailed, defining strands of fur and color patches, though it avoids pigeonholing itself into one type of animal by using the pigeons, quite possibly the best CGI creatures in the film next to Bolt. The shades on their necks blend brilliantly and the feathers are very well definied, a complete different aesthetic from dogs, cats, and hamsters. And there is, of course, the behaviours. Each animals moves with an insane amount of precision, keeping realism in tact while also allowing for some unbelievable motions to pass by unnoticed. And once again, the pigeons behave strikingly similar to the real birds, whereas the birds in Nemo, especially the seagulls, throw most attempts at detail and realism to the side for humor's sake, a compromise that Bolt does not make. Nemo makes a damn strong case to break even with Bolt, but the range in the creatures has me lean in Disney's favor.
Finally we have environments, the most varied of which are probably seen in Wall*E, Toy Story, and Nemo. It's hard to argue with how great Wall*E looks, but the color palette is never fully realized as the three primary competitors for time are the blacks of space, the browns of earth, and the whites of the ship's innards. Now the sequence in the ship when all the people are going through the mall is great, but it's a fleeting occurrence and does not remain the whole film, or change dramatically enough throughout the run time. Toy Story, once again, is great, but the age is apparent, still I'd give it the edge over most of Wall*E, and the environments used in that film are all nearly handled, or at least replaced, by the environments in Bolt, ranging from cities to lush fields of grass where the different blades are defined. Now we go to Nemo, the strongest competitor for the environment CGI. Despite being confined to the ocean the dramatic shifts in landscape from part to part. The colors are fully realized, the water is beautiful, and the land is well detailed, even the doctor's office is great. I would give these two films a push, Bolt and Nemo are even money in environment, and I may lean toward Nemo one day and Bolt the next, but as a whole Bolt is a more fully realized CGI film that still works as a cartoon/comedy. Note how I do not call Nemo a bad film, just that the CGI, as a whole, is more impressive in Bolt than in Nemo, what I consider to be Pixar's best use of CGI in any of their films.