Questions about anthologies (for readers & writers)

My flist is such a fountain of useful information, so I'm asking for your opinions on anthologies today!

I've got questions for readers and for writers… I'm in discussions with a publisher about signing on to edit a couple of anthologies, and before I finalize anything, I'd love some feedback.

Readers: I'm hoping to make the anthos LGBT only, but the pub might want some het stories in there, too. Would m/m readers buy an antho that had half het stories in it? 25% het stories? If you don't like LGBT would those stories keep you from buying an anthology? I want to appeal to a lot of readers but I don't want either group to feel they are being short-changed if they don't get enough of the content they most enjoy reading. Would you buy an antho if you like the subject, even if it's not filled with authors you already know and love?

Writers: What determines if you will sub to an anthology? The topic, editor, publisher, payment? The payment looks to be pretty small, but will include royalites, rather than just inital payment. Does that appeal to you? I'm honestly concerned about being able to attract quality stories given the budget but would kick in part of my share to get some good stuff.