I've never understood the problem people have with long books. How is one well written 600 page book any harder to read than two well written 300 page books read back to back. If you view your reading experience as a continuous one then I don't see that it makes any difference. That said a badly written book, or just one that doesn't suit you, is always going to leave a worse impression than a short one where the pain doesn't last long
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Historically there have always been long and short books. The works of Charles Dickens are not exactly short, Bronte's Jane Eyre is around 500 pages. Most of Jules Verne's books that I have seen are between 300 and 400 pages long.
In the early part of the 20C to make a living as an author you had to churn out lots of books; no time to write really long ones. There are lots of gems amongst those books but also lots of duds (even from the same author) and, in my view, one of the things that suffered in the shorter books was a lack of description and explanation in favour of more action that sold better. I'm not knocking those books, some of them are masterpieces, but I think it completely wrong to praise them just because they were short. The problem is that we only tend to read the best from that era and that colours our judgement of it.
Modern authors seem to be moving
back towards the longer books favoured in the past. This allows them to put in more description (not loved by all), create a bigger canvas (also not loved by all) and generally create a much fuller story experience. Sure that's not always going to be to everyone's taste but, again, criticising a book just because it is long is no better than praising one just because it is short.
Also remember that many of the SF authors that produced short classic books also wrote long ones; Heinlein would be a good example (though of course many criticised him for that).
Bottom line, if it's a good story, well told, then I don't mind how long or short it is.