At the time I thought N64 games looked significantly better than pretty much anything on PSX or the Saturn.
I'm sure PlayStation had some capabilities that were better, but for me the fact that everything was shimmering, aliased and even fucking pixellated made pretty much everything on them absolutely ugly, even at the time.
I suppose to a large extent it's a matter of taste. But for me something like Mario 64 looked way better than anything else on the other consoles.
Super Mario 64 uses N64's strengths very well. It looks like it uses a lot more polys than the average PS1 game but in reality the N64 only uses a handful of them to render it's big flat surfaces thanks to the perspective correction. It's colorful, cartoony worlds also hide the fact that the textures are smaller than the average textures of a PS1 game.
PS1 would have to work harder to for a game like Mario 64 because in order to render one of it's big, flat surfaces, it would have to use a spiderweb of many small polygons, otherwise the surface would be unstable and warp all over the place. The level geometry would look the same but it would have to use a lot more polys.
So yeah, PS1 does do more polys on average, but N64 uses them much more efficiently, since the PS1 needs to waste many of them to reduce the unstable warping. Which is the PS1's biggest flaw. Perspective correction on the N64 is why you get games like Mario 64 and Banjo-Kazooie (the best looking game for N64 IMO). And despite the PS1 pushing more polygons, it would still need to make sacrifices if these games were ever ported. But you can see how the PS1 uses it's polys more efficiently (and beats many similar N64 games) in racing games. You can see in games like Crash Team Racing, how the environments have more complexity VS Mario Kart or even Diddy Kong Racing.
Despite all that, the N64
does have the ability to push more polys than the PS1. A few devs proved that by using custom microcodes. The poster child game for this is World Driver Championship IMO.
The pics are from a time trial so you only see one car (it's also emulated so it's sharper than normal), but you can race against 7 other cars on the same screen and they all use as many polys as yours. These models are more detailed compared to any car model from any PS1 or Saturn game. The environments are also much more detailed compared to other N64 racers with plenty of background objects. And the frame rate is almost always steady 30fps with very little pop-up. There is another racing game from the same dev (BOSS Studios) called "Stunt Racer 64" and that also uses a ton of polygons to render it's tracks. There are quite a few late releases from several devs (like Factor 5) who used microcodes so they can make better use of the N64 hardware. All these games are far and above what the PS1 could do in terms of polygon pushing.
As far as textures are concerned, the PS1 (and Saturn) are better, there is no doubt about it. The N64 has a very small texture cache which only allows very small textures in comparison. And the fact that the N64 can render big surfaces very easily, and uses them often, means that these textures have to be stretched a lot. Which is why the textures in most games look blurrier on the N64.
This problem can be fixed, however. The developer can use a few smaller textures and stitch them together so they can make a big, detailed one. RARE did this with Banjo-Kazooie and that's why the game has amazing textures to behold:
This approach, however, is time consuming. Not every developer would bother. Not even Nintendo themselves. As a result, the average N64 game has blurry textures and combined with it's heavy anti-aliasing and a not so good video output, you got the blurry look in many N64 games.
sunnysideup
I think they look all pretty good. World Driver Championship is almost Dreamcast level, hella impressive. The thing is though, that WDC and RR Type 4 were released in 1999, whereas Sega Rally was released in 1995, so it's not exactly a fair comparison.