I had Kindle DX (9.7'), kindle 4 wifi (6'), and now I have ONYX BOOX M92. My experience is that ONYX M92 is absolutely winner. I am reading PDFs, mobi, comics i docx with no problem. I highly recommending M92. And yes, there is few very, very small bugs but Kindle don't has bugs simply because Kindle don't has as many feature as M92 has.
My vote to M92. Hope I helped.