I think ABBYY is probably the best in terms of maintaining the original formatting unfortunately. If you want
you could open a bug, attach the original ABBYY generated html book, mark it private, and have Kovid assign it to me. I maintain the function that attempts to clean up ABBYY markup, but to be honest it's had limited testing, just a few of my own docs from that I'd converted, and it's possible different versions of ABBYY generated markup won't work with the function.