Sorry no idea about the clara. Had it been the Libra colour, would recommend the one linked in the review. sidenote: I doubt you'll find one under 500.
Sorry, won't be able to give specific help here but my broad message is AVOID. I have read very few PDFs on the device so far and the experience so far has been that they are very slow to load and page turns are also slow. Won't recommend reading PDFs on this. I read PDFs on my my 8 inch Nokia T10 tablet using Xodo or Readera. Works best for me that way.