Oh sj, you are talking to someone currently selling some of her Asterix collection in order to repurchase new ones so that all the bindings match (the publishers changed mid-stream).
Wow. You're more serious than I am. I'm happy if I either have all of the same author is hardcover or paperback.
I'm not sure serious is the word you are looking for...
sj, I would get rid of it. If you don't like it, why keep it?
I'd keep it if it were part of a series but get rid of it if it's a standalone work.
I'm with Susan. I'd hate to lose the middle of a series, even if I didn't like it, but I'm thinking of paring down some of my books, and am definitely getting rid of some authors' one-off books (or series I didn't like), but keeping others. Like keeping all the Kate Elliot Jaran books, though I dont' like the last couple, but getting rid of the few I have of her other series.
They're not a series. Just one off books by authors I usually enjoy.
meara is me WRT Kate Elliott. I've tried her fantasy series, but they're too convoluted and involved even for my taste. I think of her books every time I'm tempted to add yet another POV character or subplot to my WIP....
As the daughter of a used bookstore owner, I say get rid of it. There will be someone out there who likes it, and books should be where they will be loved.
I'm of the all-one-type school. All hardcovers, or all trades, or all mass-markets, whichever. I haunt book sales and used book stores to find the right editions because ... I'm a little obsessed.
I don't need to keep all books by a specific author, though, if there's something I don't like. Unless, like others have said, it's part of a series, and then I get a weird completist thing going on.
I also almost always look for hardcovers of books I really love at sales.