my reading speed is too low from standard (about 500wpm when I tried reading fast, yeah I probably missed something while trying to do so, I guess) so the long chapters make me feel kind of overwhelmed.
Short doesn't mean the author is not trying.

I personally prefer 2500 - 5000 per chapter. I think 5000+ is alright too but verging on "when will this chapter end omg" territory.
I have a very low attention span though (when writing my own fics I tend to write a bit of one and skip over to another quite a bit. I'm not good at concentrating for long periods of time hahaha) so when a chapter is starting to get a little longer (maybe once it hits 8k or something) I start getting a little impatient hahahaha.
It doesn't mean that I don't like the story, but I tend to want to do other things and its a little difficult to bookmark your spot in a story if your chapter is extremely long.
I don't think I've actually read many stories which go too long with their chapters though (oneshots, fair enough I mean they're oneshots) but yeah chaptered fics are chaptered for a reason I guess.

omg imagine a 40+ chaptered fic with 20k word chapters o mg

Whoever has the patience, dedication and patience to read and/or write something like that - kudos to you!

As a person who takes her time to read and enjoy a chapter, I don't really have the concentration for 5000+ words, I like reading stories from 2500-5000 words.
My chapters are around 3000/3300 words long and I think they can be 4000 long...I just don't have enough patience to describe things that much xD

For a one shot, 5000 or more, but for an order going story, 2500-5000

d) 5000+

it's like reading a book which is awesome

definitely 5000+
when it's significantly less than this what is on my mind is: "is the author even trying?"

in reference to what @thirsty said: if the author is good, they're able to make really long chapters very entertaining

5000+

the story that i'm currently reading has around 20 000 words per chapter and all of the chapters are interesting