The PC-Engine (Turbografx-16 in North America) wasn't the most popular home console ever made, but it was one of the best engineered.
It was introduced in Japan when Nintendo's grey box was just picking up speed in the United States. There really was no comparison to it and the NES, in all honesty. It had eight times more colors, the sprites were four times bigger, twice as many sound channels, along with a range of other neat shit.
Remember, this was in 1987 when America was just getting aquainted with Mario and Commodore's, Apple's, and Atari's 8-bit computers were still riding high. The console itself was tiny, easily half the size of the NES, yet its optimal display without resorting to convoluted hardware tricks or even taxing the system was a mind-boggling 512x240 and could display up to 482 colors.
The machine sold like hotcakes in Japan, even with the expensively priced CD add-on. It easily dominated the scene over Sega, and even held its own against Nintendo when their 16-bit behemoth was released. It did not do so well in the United States for a number of reasons.
The Turbografx's pack-in game was a cruel joke, which looked and played like a bargain-bin NES game that Kay Bee's and Toys R Us stores became flooded with around the time. The initial crop of release games were no better - NEC America handled the system release horribly. The only game that really was a "killer app" for most of the life of the system was Splatter House, and even that lost its charm (so to speak). There was an attempt to revive the system with the TurboDuo update, a dual cartridge/CD system. The marketing failure for that attempt is still being laughed at today.
Every month in EGM, they would showcase all the new PC Engine games being released in Japan. Japan got a wide range of every genre - fighting, strategy, RPG, shooters, you name it. American players never received a fraction of those games on these shores, including sure-fire guaranteed hits like Street Fighter II: Champion Edition and Dracula (Castlevania) X: Rondo of Blood.
Another nail in the Turbo's coffin, to western video game enthusiasts anyway, was the fact that the CPU wasn't really 16-bit -- being two modified 6502s running in parallel. Nowadays we know better, but the big marketing push back in the early days of the 16-bit revolution was the bits part. It didn't matter that the engine underneath the Turbo was twice as fast and more powerful than the stock 68000 powering the Genesis. It wasn't 16-bit, and that was that - despite being probably the two most comparable machines released for any era (keep in mind Sega's machine had a few tricks the PC-E couldn't do, either.)
The whole bit war entered the realm of the ridiculous when SNK marketed their 16-bit behemoth, the Neo-Geo as 24-bit. This marketing hogwash came from the machine's pairing of a 68000 and an 8-bit Z80 - which is exactly the same two chips the Megadrive used, but anyway. Despite this retarded claim, the Neo Geo really was the most powerful console from that era, so much that it managed to keep itself officially supported by the King of Fighters series that lasted well into the days of the PS2. It was also expensive as all fuck, costing up to three times as much as any other console and the games costing easily up to $200.
So the home gamer's choices when it came to playing the arcade fighters that defined the Neo Geo at home were to buy the ridiculously expensive console itself, or play the watered-down ports for the Super Nintendo or Sega Genesis. Before the end of the PC Engine's life, a 2MB ram upgrade for the CD system (known as the Arcade Card) was released - the intention was clear to bring the Neo-Geo arcade experience to lighter wallets. It did this job fantastically, with ports using the same huge sprites and detailed backgrounds that the other two affordable systems failed to do. Not bad for an 8-bit machine.