Hyphen is my favorite ereading app, too — and I say this as someone who likes the page-curl animation (which Hyphen has).
I also don't care for fancy backgrounds — just want something plain and light-colored — so Hyphen suits me fine there, too.
What I like about MapleRead, though, is it offers a color wheel so you can pick the exact shade of background. However, that feature is not enough to make me leave Hyphen
That said, I think it's really great that there are so many terrific ereading apps to choose from now. Before this summer, reading on my iDevices was an okay experience; now it's truly enjoyable.