I think it depends on what you define as success. In my opinion it is the PS2. The reasoning? PS2 is the first console to hit over 150M units and is, so far, the best selling console ever. This is at a time when it's contemporaries sold just over 20M units. Software was not nearly as cheap to make due to a lack of cheap digital software sales like indies, yet PS2 still managed to sell more than any other console (aside from the PS4 just recently). In addition to all of this, the PS2 did this at a time when selling over 100M consoles was not guaranteed (in fact, only two other consoles did this before it) and the gaming landscape was not NEARLY as popular as it is today.
The PS4 is SUPER successful. However, I would attribute some of that success to it's major competitors shooting themselves in the foot. The Wii U started with a misstep due to it's lack of power yet high price tag and poor advertising, the Xbox One started with very controversial messaging that had to be reversed completel AND was sold at an even higher price tag than it's contemporary (PS4) for worse specs. The PS2 however? Mopped the floor with the Dreamcast to start, then when it's contemporaries showed up with better specs and even a cheaper price...still mopped the floor. It's really insane. PS2 sales just floor me every time. To be honest, it shouldn't have sold as well as it did. It was hard to program for (unlike the GC and Xbox) and didn't contain any popular innovative exclusive features (unlike the Wii or DS) yet it sold boatloads. Sony should be proud. PS4, to be honest, just followed a successful mold that was propelled even farther due to it's competition.







