Good point.

How about it, people? Would you change your answer if it was 10 vs. 90? Or even 5 vs. 95? Where's the cutoff?

Depends.

If Metascore is the measurement then I wouldn't buy the system with only 100 games since top 20 would be not enough games I would like to play (I mean, I don't want to play every game just because it has a great score)) and in the bottom 80 would be probably also not enough games for me.

Personal taste then top 20 as long as it's really enough games for me.to justify the purchase of the system. Maybe even my top 20 would have already some games I wouldn't like that much

1000+ games then probably top 20 personal taste and also with Metascore as measurement. The best 200+ reviewed games, I think that would be enough for me even if I would miss many games not as good reviewed but interesting to me. 

I would rather have the top 5 than the bottom 95.

This is a tough one.... but why should we have to choose?

Access to all 100% is obviously better.

Voted top20 though.

Meta critic for PS4 has 521 games ranked.
So top 20% would be the first 104 games.

Man its not as easy a question as you might think, if you look at it that way.
Theres plenty of great games over the 104 rank.

Would you rather have your 5 most fave games than the other 95 in your personal top 100 fave games list? Heck, would you rather have just the #1? If it was my personal top 100, and it was 5 vs 95, there are too many great games in my personal top 100 to pass over 95 of them in favour of just 5, even if my most favourite 5 are great games.

IT depends a bit. If it was my personal top 100, then I would take 20 over 80, but 95 over 5, 10 vs 90.... that's where it gets tricky.

in general i'd say i'd take quanity over "quality".  for 2 reasons:

1. i like to play a lot of games not 1 game a lot.

2. i like genres that are typically not reviewed well like puzzle and platformer.

so my problem with your poll is that top 20 is still 20 games (according to your rules) which is a lot of games.  in the meta critic distribution of games that is basically every game rated above an 80.

if we are going by review scores i'd say the "interesting" breakdown is 90 - 100 meta, 80 to 90 meta; and 70 and below meta.

90+ are great games but  very few.

80 - 90 are good games and quite a few

70 and below is a ton of games and quite a few misunderstood "gems". 

in that poll i'd go with 80-90 on the quantity over "quality" argument for sure.  as amazing as some of those 90+ games are i just couldn't deal with only a couple games a year.

In hindsight, maybe I should have asked something like "top 5 vs. bottom 15." 

Yeah, it's a tough call. The 100 greatest games I've ever played. The 20 best in one pile. The 80 "worst" in another. That's not easy.