For what it's worth, since I'm aware of the hardware behind Saturn, PC-FX, and to a lesser extent PSX, I'll help clear some stuff up.
First off, Saturn's dual SH-2s blow the PC-FX's V810 away. Even one of the SH-2s out-performs the PC-FX's CPU. PSX's MIPS is also faster than the PC-FX's V810. The V810 is just not that fast of a CPU, unfortunately (though in my professional opinion, it's probably more fun to program V810 assembly than SH-2 and MIPS).
The PC-FX has 4 backgrounds on one of the video chips (KING), of which a single background can rotate/scale. These backgrounds are fairly powerful though; they can do all sorts of neat video modes per-background, which is interesting to play with. It has 2 more backgrounds, each one generated by a 7up (the same video chip that was in the PCE), which don't really have anything special. Those chips together also can generate a total of 128 sprites, 32 per scanline. And then we have 1 more background, which comes from the MJPEG decoder, which is actually where the PC-FX beat out all the other consoles of the generation. The PC-FX's MJPEG decoder can play JPEG video streams along with Redbook audio at a very pleasant 30 fps.
On the other hand, you've got Saturn with a full 3D renderer, and 4 background layers, 2 of which can rotate/scale. The 3D renderer gives it a nearly unlimited sprite count, and "virtual" backgrounds, without any per-scanline limitations. It lacks an MJPEG decoder, though I believe it has some sort of hardware acceleration for FMV, but it does not run at a consistant 30 fps, in any case.
The PC-FX's audio chip, SoundBox, is basically the sound chip from the PCE with 2 stereo ADPCM channels, and the ability to stream redbook audio. It's very not-fancy, though it certainly gets the job done.
The Saturn has a whole processor dedicated to handling any sound tasks, has 3 timers, a DMA channel, a full Yamaha FM sound generator, MIDI input support (not the general MIDI soundfont, it's a way to control the sound channels), and a total of 32 sound channels (which can be mixed and matched between FM and PCM) with a DSP that can apply 16 different effects.
In essence, the PC-FX was rather low-power for the time, however if they had actually released it with the 3D chip that was on their PC-FXGA boards, it might have stood a chance (the fill-rate, though slower than the Saturn even, was not too bad).
Also, I fully expect us homebrewers to be able to unlock the full power of this device; it's basically a PC-Engine on super-steroids, though we rarely saw anything that was even as good as most PCE software.
I've asked before, and I'll ask again. Someone port Doom to the FX. Sure Doom is on everything known to man, but the FX needs it. Also the PS1 and Saturn Doom ports are terrible, a good 32-bit console port needs to be made! DO IT!
Haha, I'm sorry, that will probably never happen. The PC-FX just doesn't have the sprite power to do it unfortunately.