Best how?
Best hardware in terms of long lasting quality
Best hardware in terms of power
Best hardware in terms of games available
Best hardware in terms of ease of programming
Best hardware in terms of allowing me to do what I want to do
If we are limiting it to the current big three (Sega, Commodore, Amstrad, BBC, Acorn, Atari... all doing console type things in years past) then that gets tricky.
In terms of quality then all three have had some utterly egregious failures in the quality department for many many years. If I limit it to best possible options then probably the later stage revisions of Microsoft hardware, however they had some howlers and very dubious choices before getting there. Sony tend to take the middle path of nothing I expect to still be ticking in 20 years (though lasers are a part of that) but dodging too many outrageous acts.
Power wise then each have competed for top spot or near enough that at various points, even if Nintendo gave up some years back. At this point it is more or less off the shelf hardware with nothing particularly interesting done as far as games are concerned (or in terms of end results that interesting -- the PS3 cell stuff was nothing much in the end). I might mention controllers in this but other than Nintendo doing some gimmicks and failing to put said gimmicks in a conventionally good controller I have nothing really.
Games wise then I occasionally do a thing where I consider what allows me to experience games of the day, and for many years now (but not always) that has been the PC which none of the consoles really stack up against. PS1 era then the N64 had some interesting efforts and some people attempting ports, and the Saturn some things not recognised as classics, but there was nothing really in it and the PS1 was it. PS2 then while the gamecube and xbox were comparative powerhouses, and the xbox sported some nice stuff then PS2 again probably has it. I reckon the 360 won the next race, the wii more or less stepped out to play with shovelware and the PS3 eventually caught up and kind of matched the 360 but ignoring PC then the 360 was probably the gamer's machine and arguably still is for that generation. This last go around then the xbone faceplanted hard but has made reasonable efforts to catch up, Nintendo did nothing with the Wii U and the Switch (assuming it is part of this generation) is mostly doing the Portendo thing and is lacking any of the magic of the GBA and DS for me, which leaves the PS4 as likely winner here even if I don't know if I have more than about 3 games I will remember* in 10 years for it.
*my game collecting tends to be games I want to play and games that were first or a notable evolution in a given style/mechanic. I don't know what I would put down for the PS4 here.
Best hardware in terms of ease of programming. So probably not the PS3 and definitely not the Saturn. Nintendo going the other way have also made some very odd decisions and hamstrung people as a result (powerpc of that architecture on the gamecube was a bold choice for something that late in its relevance, was very questionable for the Wii and utterly insane for the Wii U, going for their handhelds then the DS' dual CPUs was kind of obviated by their dev kit and the 3ds' 3d offering was a bit of a bodge really).
Allowing me to do what I want. None are open systems really so Nintendo seem to have the worst security and would win that by omission for their earlier consoles, however owing to very nice alternatives popping up and PCs finally realising people like to plug things into their TV... homebrew isn't what it used to be. All three have pissed in my cereal in terms of lawsuits and legal bullying4, though amusingly MS is probably the least (that amusing kinect hacking stuff aside) which I doubt anybody following 90s MS would have expected, and Sony have long since won themselves a continuing place on my "don't buy unless absolutely necessary" list for their actions. Censorship wise then all three have bad things to their name, overt and more subtle things we only find out from developer interviews years after the fact.
So yeah I guess I would not mourn the passing of any of them at this point, or indeed all three at once.