ShuBook has trouble getting basic formatting right, and is therefore, unfortunately, no Stanza replacement.
Try loading this basic EPUB test file in ShuBook:
(credit goes to whoever posted it first in these MobileRead forums)
When ShuBook displays this test file properly, then we can talk.
I'm still on Stanza on my iPhone, and I'm keeping my iPhone on iOS 5, so that Stanza more or less works properly.
I already know what Stanza's replacement on the iPhone will be, though: Marvin
. Check it out here:
I can pretty much guarantee Marvin will knock your socks off.
The iPhone version is due to arrive within the next few months.